Photosensitive composition, pattern-forming method using the photosensitve composition and compound in the photosensitive composition

ABSTRACT

A photosensitive composition containing a compound having a specific structure as described in the specification, a pattern-forming method using the photosensitive composition and the compound having a specific structure used in the photosensitive composition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photosensitive composition capable ofchanging the property by reaction upon irradiation with actinic ray orradiation, a pattern-forming method using the photosensitivecomposition, and the compounds in the photosensitive composition. Morespecifically, the invention relates to a photosensitive composition foruse in a manufacturing process of semiconductors, e.g., IC, themanufacture of circuit substrates for liquid crystals, thermal heads andthe like, and other photo-fabrication processes, lithographic printingplates, and acid-hardening compositions, and also the invention relatesto a pattern-forming process using the photosensitive composition, andthe compounds in the photosensitive composition.

2. Description of the Related Art

Chemical amplification resist compositions are pattern-forming materialscapable of generating an acid at the area irradiated with actinic raysuch as a far ultraviolet ray or radiation, changing the solubility in adeveloper of the irradiated area with the actinic ray or radiation andthe solubility of the non-irradiated area by the reaction with the acidas a catalyst, and forming a pattern on a substrate.

When a KrF excimer laser is used as the exposure light source, resinshaving poly(hydroxystyrene) that is small in absorption in the region of248 nm as a fundamental skeleton are mainly used, so that a highsensitivity, high resolution and good pattern is formed as compared withconventionally used naphthoquinonediazide/novolak resins.

On the other hand, when a light source of further shorter wavelength,e.g., an ArF excimer laser (193 nm), is used as the exposure lightsource, since compounds having an aromatic group substantially showlarge absorption in the region of 193 nm, resists containing a resinhaving a highly transparent alicyclic hydrocarbon structure have beendeveloped for an ArF excimer laser.

Various compounds have been found as to acid generators that are mainconstitutional components of chemical amplification resists, e.g.,triaryl sulfonium salts and arylalkyl sulfonium salts are reported(e.g., refer to JP-A-2000-275845 and JP-A-10-48814).

As generating acids, e.g., in JP-A-2002-131897 and JP-A-2003-149812,specific fluorinated organic sulfonic acids are used. In JP-T-11-501909(The term “JP-T” as used herein refers to a “published Japanesetranslation of a PCT application”.), JP-A-2002-268223 andJP-A-2003-246786, imido anion acid generators capable of generatinghighly acidic imido upon irradiation with actinic ray or radiation areused.

However, these compounds are still insufficient in various points andthe improvement in line edge roughness, exposure latitude and the likeis required.

In the optical microscope, as a technique of enhancing resolution, amethod of filling in between a projection lens and a sample with aliquid having a high refractive index (hereinafter referred to as“immersion liquid”), i.e., an immersion method is conventionally known.

As “the effect of immersion”, resolution and the depth of focus can beexpressed by the following expressions in the case of immersion, with λ₀as the wavelength of the exposure light in the air, n as the refractiveindex of immersion liquid to the air, and NA₀=sin θ with θ asconvergence half angle of the ray of light:Resolution=k ₁·(λ₀ /n)/NA ₀Depth of focus=±k ₂·(λ₀ /n)/NA ₀ ²

That is, the effect of immersion is equivalent to the case of usingexposure wavelength of the wavelength of 1/n. In other words, in thecase of the projection optical system of the same NA, the depth of focuscan be made n magnifications by immersion. This is effective for everypattern form, and further, it is possible to combine an immersion methodwith super resolution techniques such as a phase shift method and atransformation lighting method now under discussion.

The example of the apparatus applying this effect to the transfer of amicro-fine image pattern of a semiconductor element are introduced inJP-A-57-153433 (the term “JP-A” as used herein refers to an “unexaminedpublished Japanese patent application”) and JP-A-7-220990.

The latest technical advancement of immersion exposure is reported inSPIE Proc., 4688, 11 (2002), J. Vac. Sci. Tecnol. B, 17 (1999), SPIEProc., 3999, 2 (2000), and WO 2004/077158. When an ArF excimer laser isused as the light source, it is thought that pure water (having arefractive index of 1.44 at 193 nm) is most promising as the immersionliquid in the light of the safety in handling, the transmittance and therefractive index at 193 nm. When an F2 excimer laser is used as thelight source, a solution containing fluorine is discussed from thebalance of the transmittance and the refractive index at 157 nm, but asufficiently satisfactory solution from the viewpoint of theenvironmental safety and at the point of refractive index has not beenfound yet. From the extent of the effect of immersion and the degree ofcompletion of resist, it is thought that immersion exposure techniquewill be carried on an ArF exposure apparatus earliest.

It is appointed that when a chemical amplification resist is applied toimmersion exposure, the resist layer is brought into contact with theimmersion liquid at the time of exposure, so that the resist layerdecomposes and ingredients that adversely influence the immersion liquidooze from the resist layer. WO 2004/068242 discloses that resistperformance decomposes by the immersion of a resist for ArF exposure inwater before and after exposure and appoints this is a problem inimmersion exposure.

SUMMARY OF THE INVENTION

An object of the invention is to provide a photosensitive compositionthat shows good line edge roughness and exposure latitude, and improvedin the contrast of sensitivity and dissolution in UV exposure. Anotherobject is to provide a pattern-forming method using the photosensitivecomposition. A further object is to provide compounds in thephotosensitive composition. Still further objects of the invention areto provide a photosensitive composition suitable for immersion exposurehaving good performances as described above even in immersion exposure,to provide a pattern-forming method using the photosensitivecomposition, and to provide compounds in the photosensitive composition.

The present invention is as follows.

(1) A photosensitive composition, which comprises (A) a compound capableof generating an organic acid represented by formula (I) uponirradiation with actinic ray or radiation:Z—A—X—B—R  (I)

wherein Z represents an organic acid group;

A represents a divalent linking group;

X represents a single bond or a divalent linking group having a heteroatom;

B represents a single bond, an oxygen atom or—N(Rx)—;

Rx represents a hydrogen atom or a monovalent organic group; and

R represents a monovalent organic group having a bond that is cut by anaction of an acid, and when B represents —N(Rx)—, R and Rx may be bondedto form a ring.

(2) The photosensitive composition as described in (1) above, wherein Zrepresents a sulfo group or a carboxyl group.

(3) The photosensitive composition as described in (1) or (2) above,wherein A represents an alkylene group.

(4) The photosensitive composition as described in (3) above, wherein Arepresents an alkylene group in which a part or whole of hydrogen atomsis substituted with fluorine atoms.

(5) The photosensitive composition as described in any of (1) to (4)above, wherein X is selected from the group consisting of a single bond,—SO₂—, —SO—and —CO—.

(6) The photosensitive composition as described in any of (1) to (5)above, wherein the compound capable of generating an organic acidrepresented by formula (I) upon irradiation with actinic ray orradiation is a sulfonium salt compound of an organic acid represented byformula (I) or an iodonium salt compound of an organic acid representedby formula (I).

(7) A pattern-forming method, which comprises:

forming a photosensitive film with a photosensitive composition asdescribed in any of (1) to (6) above; and

exposing and developing the photosensitive film.

(8) An organic acid represented by formula (I) and a salt of the organicacid:Z—A—X—B—R  (I)

wherein Z represents an organic acid group;

A represents a divalent linking group;

X represents a single bond or a divalent linking group having a heteroatom;

B represents a single bond, an oxygen atom or —N(Rx)—;

Rx represents a hydrogen atom or a monovalent organic group; and

R represents a monovalent organic group having a bond that is cut by anaction of an acid, and when B represents —N(Rx)—, R and Rx may be bondedto form a ring.

(9) A compound capable of generating an organic acid represented byformula (I) upon irradiation with actinic ray or radiation:Z—A—X—B—R  (I)

wherein Z represents an organic acid group;

A represents a divalent linking group;

X represents a single bond or a divalent linking group having a heteroatom;

B represents a single bond, an oxygen atom or —N(Rx)—;

Rx represents a hydrogen atom or a monovalent organic group; and

R represents a monovalent organic group having a bond that is cut by anaction of an acid, and when B represents —N(Rx)—, R and Rx may be bondedto form a ring.

As preferred embodiments of the invention, the following constitutionsare exemplified.

(10) The photosensitive composition as described in any of (1) to (6)above, which further comprises (B) a compound capable of generating anacid upon irradiation with actinic ray or radiation.

(11) The photosensitive composition as described in (10) above, whereinthe compound of component (B) is a sulfonium salt of afluorine-substituted alkanesulfonic acid, a fluorine-substitutedbenzenesulfonic acid or a fluorine-substituted imidic acid.

(12) The positive photosensitive composition as described in any of (1)to (6), (10) and (11) above, which further comprises (C) a resin capableof decomposing by an action of an acid to increase solubility in analkali developing solution.

(13) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has a fluorine atom on a main chainor side chain.

(14) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has a hexafluoroisopropanolstructure.

(15) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has a hydroxystyrene structural unit.

(16) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has at least one repeating unitselected from the group consisting of 2-alkyl-2-adamantyl (meth)acrylateand dialkyl(1-adamantyl)methyl (meth)acrylate.

(17) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has a monocyclic or polycyclicalicyclic hydrocarbon structure.

(18) The positive photosensitive composition as described in (17) above,wherein the resin of component (C) has at least one repeating unitselected from the group consisting of 2-alkyl-2-adamantyl (meth)acrylateand dialkyl(1-adamantyl)methyl (meth)acrylate, at least one repeatingunit having a lactone structure and at least one repeating unit having ahydroxyl group.

(19) The positive photosensitive composition as described in (18) above,wherein the resin of component (C) further has a repeating unit having acarboxyl group.

(20) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has a silicon atom on a main chain orside chain.

(21) The positive photosensitive composition as described in (12) above,wherein the resin of component (C) has a repeating unit having a lactonestructure.

(22) The positive photosensitive composition as described in any of (12)to (21) above, which further comprises (D) a dissolution inhibitingcompound capable of decomposing by an action of an acid to increasesolubility in an alkali developing solution and having a molecularweight of 3,000 or less.

(23) The positive photosensitive composition as described in any of (1)to (6), (10) and (11) above, which further comprises:

(E) a resin soluble in an alkali developing solution; and

(D) a dissolution inhibiting compound capable of decomposing by anaction of an acid to increase solubility in an alkali developingsolution and having a molecular weight of 3,000 or less.

(24) The negative photosensitive composition as described in any of (1)to (6), (10) and (11) above, which further comprises:

(E) a resin soluble in an alkali developing solution; and

(F) an acid crosslinking agent capable of crosslinking with the resinsoluble in an alkali developing solution by an action of an acid.

(25) The photosensitive composition as described in any of(1) to (6) and(10) to (24) above, which further comprises at least one of (G) a basiccompound and (H) a fluorine and/or silicon surfactant.

(26) The photosensitive composition as described in (25) above, whereinthe basic compound (G) is a compound having a structure selected fromthe group consisting of an imidazole structure, a diazabicyclostructure, an onium hydroxide structure, an onium carboxylate structure,a trialkylamine structure, an aniline structure and a pyridinestructure, an alkylamine derivative having at least one of a hydroxylgroup and an ether bond or an aniline derivative having at least one ofa hydroxyl group and an ether bond.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described in detail below.

In the description of a group (an atomic group) in the specification ofthe invention, the description not referring to substitution orunsubstitution includes both a group not having a substituent and agroup having a substituent. For example, “an alkyl group” includes notonly an alkyl group having no substituent (an unsubstituted alkyl group)but also an alkyl group having a substituent (a substituted alkylgroup).

A positive photosensitive composition in the invention, preferably apositive resist composition, contains (A) a compound capable ofgenerating an organic acid represented by formula (I), and (C) a resincapable of decomposing by the action of an acid to increase solubilityin an alkali developing solution, and if necessary, further contains (B)a compound capable of generating an acid upon irradiation with actinicray or radiation, and (D) a dissolution inhibiting compound capable ofdecomposing by the action of an acid to increase solubility in an alkalideveloping solution having a molecular weight of 3,000 or less,alternatively, contains (A) a compound capable of generating an organicacid represented by formula (I), (E) a resin soluble in an alkalideveloping solution, and (D) a dissolution inhibiting compound capableof decomposing by the action of an acid to increase solubility in analkali developing solution having a molecular weight of 3,000 or less,and if necessary, further contains (B) a compound capable of generatingan acid upon irradiation with actinic ray or radiation.

A negative photosensitive composition in the invention, preferably anegative resist composition, contains (A) a compound capable ofgenerating an organic acid represented by formula (I), (E) a resinsoluble in an alkali developing solution, and (F) an acid crosslinkingagent capable of crosslinking with the resin soluble in an alkalideveloping solution by the action of an acid, and if necessary, furthercontains (B) a compound capable of generating an acid upon irradiationwith actinic ray or radiation.

[1] (A) A Compound Capable of Generating an Organic Acid Represented byFormula (I) upon Irradiation with Actinic Ray or Radiation:

A photosensitive composition in the invention contains a compoundcapable of generating an organic acid represented by the followingformula (I) upon irradiation with actinic ray or radiation (alsoreferred to as “compound (A)”).Z—A—X—B—R  (I)

In formula (I), Z represents an organic acid group; A represents adivalent linking group; X represents a single bond or a divalent linkinggroup having a hetero atom; B represents a single bond, an oxygen atomor —N(Rx)—; Rx represents a hydrogen atom or a monovalent organic group;and R represents a monovalent organic group having a bond that is cut bythe action of an acid; and when B represents —N(Rx)—, R and Rx may bebonded to form a ring.

Compound (A) generates an organic acid represented by formula (I) uponirradiation with actinic ray or radiation such as an excimer laser,e.g., KrF, ArF, etc. The organic acid represented by formula (I) has abond that is cut by the action of an acid in the molecule. At this time,the acid that decomposes the organic acid represented by formula (I) maybe the organic acid itself generated from compound (A), or may be otheracids. As other acids, acids generated upon irradiation with actinic rayor radiation from acid generators usable in combination described laterare exemplified. Resolution increases by the use of compound (A) in aphotosensitive composition.

In formula (I), R represents a monovalent organic group having a bondthat is cut by the action of an acid.

The bond cut by the action of an acid can be formed, e.g., by thefollowing shown amido bond, ester bond, acetal bond, carbamoyl bond, orcarbonate bond.

The bond cut by the action of an acid is preferably formed by an esterbond, an acetal bond or a carbonate bond, and more preferably formed byan ester bond or an acetal bond. The ester bond is preferably such thatan oxygen atom is bonded to a tertiary carbon atom. The acetal bond maybe such that two oxygen atoms are respectively bonded to carbon atoms,and these carbon atoms are bonded to each other directly or via alinking group to form a ring.

The monovalent organic group having a bond that is cut by the action ofan acid represented by R is formed by bonding a plurality (preferablyfrom 2 to 4, more preferably from 2 to 3) of organic groups (R′) viasingle bonds and/or divalent linking groups, and at least one of thedivalent linking groups is a bond that is cut by the action of an acid.The number of the bond cut by the action of an acid is preferably from 1to 3, and more preferably 1.

As such organic groups (R′), e.g., an alkyl group, a cycloalkyl group,an aryl group, an aralkyl group, an alkenyl group, an alkoxyl group, analkoxycarbonylamino group, and a cyano group are exemplified. Aplurality of organic groups (R′) may be the same or different, and theymay be bonded to each other to form a ring.

The alkyl group as organic group (R′) may have a substituent, and thealkyl group is preferably a straight chain or branched alkyl grouphaving from 1 to 30 carbon atoms, and an oxygen atom, a sulfur atom, ora nitrogen atom may be contained in the alkyl chain. Specifically,straight chain alkyl groups, e.g., a methyl group, an ethyl group, ann-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group,an n-octyl group, an n-dodecyl group, an n-tetradecyl group, and ann-octadecyl group, and branched alkyl groups, e.g., an isopropyl group,an isobutyl group, a t-butyl group, a neopentyl group, and a2-ethylhexyl group are exemplified.

The cycloalkyl group as organic group (R′) may have a substituent, andthe cycloalkyl group is preferably a cycloalkyl group having from 3 to20 carbon atoms, and may be polycyclic, and may have an oxygen atom inthe ring. Specifically, a cyclopropyl group, a cyclopentyl group, acyclohexyl group, a norbornyl group, and an adamantyl group areexemplified.

The aryl group as organic group (R′) may have a substituent, and thearyl group is preferably an aryl group having from 6 to 14 carbon atoms,e.g., a phenyl group and a naphthyl group are exemplified.

The aralkyl group as organic group (R′) may have a substituent, and thearalkyl group is preferably an aralkyl group having from 7 to 20 carbonatoms, e.g., a benzyl group, a phenethyl group, a naphthylmethyl group,and a naphthylethyl group are exemplified.

As the alkenyl group as organic group (R′), groups having a double bondon an arbitrary position of the above alkyl group and cycloalkyl groupare exemplified.

The alkoxyl group, and the alkoxyl group in the alkoxycarbonylaminogroup as organic group (R′) is preferably an alkoxyl group having from 1to 30 carbon atoms, e.g., a methoxy group, an ethoxy group, a propoxygroup, an n-butoxy group, a pentyloxy group, a hexyloxy group, and aheptyloxy group are exemplified.

As the substituents that the above each organic group (R′) may have,e.g., a halogen atom, a hydroxyl group, a nitro group, a cyano group, acarboxyl group, a carbonyl group, a cycloalkyl group (preferably havingfrom 3 to 10 carbon atoms), an aryl group (preferably having from 6 to14 carbon atoms), an alkoxyl group (preferably having from 1 to 10carbon atoms), an acyl group (preferably having from 2 to 20 carbonatoms), an acyloxy group (preferably having from 2 to 10 carbon atoms),an alkoxycarbonyl group (preferably having from 2 to 20 carbon atoms),and an aminoacyl group (preferably having from 2 to 10 carbon atoms) areexemplified. Of the cyclic structure in the aryl group and cycloalkylgroup, an alkyl group (preferably having from 1 to 10 carbon atoms) canbe exemplified as a further substituent. Of the aminoacyl group, one ortwo alkyl groups (preferably having from 1 to 10 carbon atoms) can beexemplified as a further substituent.

As the organic acid group represented by Z, for example, a sulfo group,a carboxyl group, etc., are exemplified, and a sulfo group is preferred,by which sensitivity is increased.

The divalent linking group represented by A is preferably a divalentorganic group having from 1 to 8 carbon atoms, e.g., an alkylene group,an arylene group (preferably a phenylene group), etc., are exemplified.The divalent linking group represented by A is more preferably analkylene group, and the carbon atom number is preferably from 1 to 6,and more preferably from 1 to 4. A linking group such as an oxygen atomor a sulfur atom may be contained in the alkylene chain. The alkylenegroup may be substituted with a fluorine atom, and in that case, analkylene group in which from 30 to 100% of the hydrogen atom number issubstituted with fluorine atoms is preferred, and it is more preferredfor the carbon atom bonded to Z to have a fluorine atom. Aperfluoroalkylene group is preferred, and a perfluoroethylene group, aperfluoro-propylene group and a perfluorobutylene group are especiallypreferred, by which sensitivity is increased.

As the divalent linking group having a hetero atom represented by X,e.g., —SO₂—, —SO—and —CO—are exemplified.

X preferably represents a single bond, —SO₂—, —SO—or —CO—.

The monovalent organic group represented by Rx has preferably from 1 to40 carbon atoms, and more preferably from 4 to 30 carbon atoms, e.g., analkyl group, a cycloalkyl group, an aryl group, an aralkyl group, analkenyl group, an alkoxyl group, an alkoxycarbonylamino group, and acyano group can be exemplified. When a plurality of organic groups Rx'sare present, the plurality of organic groups Rx's may be the same ordifferent.

The alkyl group as organic group Rx may have a substituent, and thealkyl group is preferably a straight chain or branched alkyl grouphaving from 1 to 30 carbon atoms, and an oxygen atom, a sulfur atom, ora nitrogen atom may be contained in the alkyl chain. Specifically,straight chain alkyl groups, e.g., a methyl group, an ethyl group, ann-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group,an n-octyl group, an n-dodecyl group, an n-tetradecyl group, and ann-octadecyl group, and branched alkyl groups, e.g., an isopropyl group,an isobutyl group, a t-butyl group, a neopentyl group, and a2-ethylhexyl group are exemplified.

The cycloalkyl group as organic group Rx may have a substituent, and thecycloalkyl group is preferably a cycloalkyl group having from 3 to 20carbon atoms, and the cycloalkyl group may be polycyclic, or may have anoxygen atom in the ring. Specifically, a cyclopropyl group, acyclopentyl group, a cyclohexyl group, a norbomyl group, and anadamantyl group are exemplified.

The aryl group as organic group Rx may have a substituent, and the arylgroup is preferably an aryl group having from 6 to 14 carbon atoms,e.g., a phenyl group and a naphthyl group are exemplified.

The aralkyl group as organic group Rx may have a substituent, and thearalkyl group is preferably an aralkyl group having from 7 to 20 carbonatoms, e.g., a benzyl group, a phenethyl group, a naphthylmethyl group,and a naphthylethyl group are exemplified.

As the alkenyl group as organic group Rx, groups having a double bond onan arbitrary position of the above alkyl group and cycloalkyl group areexemplified.

The alkoxyl group, and the alkoxyl group in the alkoxycarbonylaminogroup as organic group Rx is preferably an alkoxyl group having from 1to 30 carbon atoms, e.g., a methoxy group, an ethoxy group, a propoxygroup, an n-butoxy group, a pentyloxy group, a hexyloxy group, and aheptyloxy group are exemplified.

As the substituents that the above each organic group Rx may furtherhave, e.g., a halogen atom, a hydroxyl group, a nitro group, a cyanogroup, a carboxyl group, a carbonyl group, a cycloalkyl group(preferably having from 3 to 10 carbon atoms), an aryl group (preferablyhaving from 6 to 14 carbon atoms), an alkoxyl group (preferably havingfrom 1 to 10 carbon atoms), an acyl group (preferably having from 2 to20 carbon atoms), an acyloxy group (preferably having from 2 to 10carbon atoms), an alkoxycarbonyl group (preferably having from 2 to 20carbon atoms), and an aminoacyl group (preferably having from 2 to 10carbon atoms) are exemplified. Of the cyclic structure in the aryl groupand cycloalkyl group, an alkyl group (preferably having from 1 to 10carbon atoms) can be exemplified as a further substituent. Of theaminoacyl group, one or two alkyl groups (preferably having from 1 to 10carbon atoms) can be exemplified as a further substituent.

Organic group Rx has a bond that is cut by the action of an acid, andthe structure may be the same as organic group R having a bond that iscut by the action of an acid.

When B represents—N(Rx)—, R and Rx, that is, one of organic groups (R′)for forming R and Rx may be bonded to each other to form a ring. Byforming a cyclic structure, stability increases and the preservationstability of the composition using the compound is improved. The ring tobe formed has preferably from 4 to 20 carbon atoms, and may bemonocyclic or polycyclic.

The organic acid represented by formula (I) and a salt thereof are novelcompounds.

The organic acid represented by formula (I) can be synthesized accordingto general sulfonic acid esterification reaction or sulfonamidationreaction. For example, the organic acid represented by formula (I) canbe obtained by a method of reacting a sulfonyl halide portion of oneside of a bis-sulfonyl halide compound selectively with amine, alcoholand the like containing a partial structure represented by formula (I)to form a sulfonamido bond, a sulfonic ester bond, and then hydrolyzinga sulfonyl halide portion of the other side, or by a method of ringopening reaction of cyclic sulfonic acid anhydride with amine andalcohol containing a partial structure represented by formula (I). Theamine and alcohol containing a partial structure represented by formula(I) can be synthesized by the reaction of amine and alcohol withanhydride such as (R′O₂C)₂O and R′O₂CCl, and an acid chloride compoundin the presence of a base.

Compound (A) is preferably a sulfonium salt compound or iodonium saltcompound of the organic acid represented by formula (I), and morepreferably a compound represented by the following formula (A1) or (A2).

In formula (A1), R₂₀₁, R₂₀₂ and R₂₀₃ each represents an organic group;and X⁻ represents an anion of the organic acid represented by formula(I).

The number of carbon atoms of the organic groups represented by R₂₀₁,R₂₀₂ and R₂₀₃ is generally from 1 to 30, and preferably from 1 to 20.

Any two of R₂₀₁, R₂₀₂ and R₂₀₃ may be bonded to each other to form acyclic structure, and an oxygen atom, a sulfur atom, an ester bond, anamido bond or a carbonyl group may be contained in the ring. As thegroup formed by bonding any two of R₂₀₁, R₂₀₂ and R₂₀₃, an alkylenegroup (e.g., a butylene group and a pentylene group) can be exemplified.

As the specific examples of the organic groups represented by R₂₀₁, R₂₀₂and R₂₀₃, the corresponding groups in compounds (A1a), (A1b) and (A1c)described later can be exemplified.

The compound represented by formula (A1) may be a compound having aplurality of structures represented by formula (A1). For example, thecompound represented by formula (A1) may be a compound having astructure that at least one of R₂₀₁, R₂₀₂ and R₂₀₃ of the compoundrepresented by formula (A1) is bonded to at least one of R₂₀₁, R₂₀₂ andR₂₀₃ of another compound represented by formula (A1).

The following compounds (A1a), (A1b) and (A1c) can be exemplified asmore preferred components (A1).

Compound (A1a) is an arylsulfonium compound in which at least one ofR₂₀₁, R₂₀₂ and R₂₀₃ in formula (A1) represents an aryl group, that is, acompound having arylsulfonium as a cation.

All of R₂₀₁, R₂₀₂ and R₂₀₃ of the arylsulfonium compound may be arylgroups, or a part of R₂₀₁, R₂₀₂ and R₂₀₃ may be an aryl group and theremainder may be an alkyl group or a cycloalkyl group.

As the arylsulfonium compound, e.g., a triarylsulfonium compound, adiarylalkylsulfonium compound, a diarylcyclo-alkylsulfonium compound, anaryldialkylsulfonium compound, an aryldicycloalkylsulfonium compound,and an arylalkylcyclo-alkylsulfonium compound can be exemplified.

As the aryl group of the arylsulfonium compound, an aryl groupconsisting of hydrocarbon, and a heteroaryl group having a hetero atom,such as a nitrogen atom, a sulfur atom, or an oxygen atom areexemplified. As the aryl groups consisting of hydrocarbon, a phenylgroup and a naphthyl group are preferred, and a phenyl group is morepreferred. As the heteroaryl groups, e.g., a pyrrole group, an indolegroup, a carbazole group, a furan group, a thiophene group, etc., areexemplified, and an indole group is preferred. When the arylsulfoniumcompound has two or more aryl groups, these two or more aryl groups maybe the same or different.

The alkyl group that the arylsulfonium compound may have according tonecessity is preferably a straight chain or branched alkyl group havingfrom 1 to 15 carbon atoms, e.g., a methyl group, an ethyl group, apropyl group, an n-butyl group, a sec-butyl group, and a t-butyl groupcan be exemplified.

The cycloalkyl group that the arylsulfonium compound may have accordingto necessity is preferably a cycloalkyl group having from 3 to 15 carbonatoms, e.g., a cyclopropyl group, a cyclobutyl group and a cyclohexylgroup can be exemplified.

The aryl group, alkyl group and cycloalkyl group represented by R₂₀₁,R₂₀₂ and R₂₀₃ may have a substituent, e.g., an alkyl group (e.g., havingfrom 1 to 15 carbon atoms), a cycloalkyl group (e.g., having from 3 to15 carbon atoms), an aryl group (e.g., having from 6 to 14 carbonatoms), an alkoxyl group (e.g., having from 1 to 15 carbon atoms), ahalogen atom, a hydroxyl group, and a phenylthio group are exemplifiedas the examples of the substituents. The preferred substituents are astraight chain or branched alkyl group having from 1 to 12 carbon atoms,a cycloalkyl group having from 3 to 12 carbon atoms, and a straightchain, branched, or cyclic alkoxyl group having from 1 to 12 carbonatoms, and the especially preferred substituents are an alkyl grouphaving from 1 to 4 carbon atoms and an alkoxyl group having from 1 to 4carbon atoms. The substituent may be substituted on any one of three ofR₂₀₁, R₂₀₂ and R₂₀₃, or may be substituted on all of the three. WhenR₂₀₁, R₂₀₂ and R₂₀₃ each represents an aryl group, it is preferred thatthe substituent be substituted on the p-position of the aryl group.

Compound (A1b) is described below.

Compound (A1b) is a compound in the case where R₂₀₁, R₂₀₂ and R₂₀₃ informula (A1) each represents an organic group not having an aromaticring. The aromatic ring here also includes an aromatic ring having ahetero atom.

The organic group not having an aromatic ring represented by R₂₀₁, R₂₀₂and R₂₀₃ generally has from 1 to 30 carbon atoms, and preferably from 1to 20 carbon atoms.

R₂₀₁, R₂₀₂ and R₂₀₃ each preferably represents an alkyl group, acycloalkyl group, an allyl group, or a vinyl group, more preferablyrepresents a straight chain or branched 2-oxoalkyl group, a2-oxocycloalkyl group, or an alkoxy-carbonylmethyl group, and especiallypreferably a straight chain or branched 2-oxoalkyl group.

The alkyl group represented by R₂₀₁, R₂₀₂ and R₂₀₃ may be eitherstraight chain or branched, and is preferably a straight chain orbranched alkyl group having from 1 to 20 carbon atoms, e.g., a methylgroup, an ethyl group, a propyl group, a butyl group, and a pentyl groupcan be exemplified. As the alkyl group represented by R₂₀₁, R₂₀₂ andR₂₀₃, more preferably a straight chain or branched 2-oxoalkyl group, andan alkoxycarbonylmethyl group can be exemplified.

The cycloalkyl group represented by R₂₀₁, R₂₀₂ and R₂₀₃ is preferably acycloalkyl group having from 3 to 10 carbon atoms, e.g., a cyclopentylgroup, a cyclohexyl group and a norbonyl group can be exemplified. Thecycloalkyl group represented by R₂₀₁, R₂₀₂ and R₂₀₃ is more preferably a2-oxocycloalkyl group.

As the straight chain or branched 2-oxoalkyl group represented by R₂₀₁,R₂₀₂ and R₂₀₃ may have a double bond in the ring, and preferably a grouphaving >C═O at the 2-position of the above alkyl group can beexemplified.

As the 2-oxocycloalkyl group represented by R₂₀₁, R₂₀₂ and R₂₀₃ may havea double bond in the ring, and preferably a group having >C═O at the2-position of the above cycloalkyl group can be exemplified.

As the alkoxyl group in the alkoxycarbonylmethyl group represented byR₂₀₁, R₂₀₂ and R₂₀₃, preferably an alkoxyl group having from 1 to 5carbon atoms, e.g., a methoxy group, an ethoxy group, a propoxy group, abutoxy group, and a pentoxy group can be exemplified.

R₂₀₁, R₂₀₂ and R₂₀₃ may further be substituted with a halogen atom, analkoxyl group (e.g., having from 1 to 5 carbon atoms), an alkoxycarbonylgroup (e.g., having from 1 to 5 carbon atoms), a hydroxyl group, a cyanogroup, or a nitro group.

Compound (A1c) is a compound represented by the following formula (A1c)and has an arylacylsulfonium salt structure.

In formula (A1c), R₂₁₃ represents an aryl group that may have asubstituent, and the aryl group is preferably a phenyl group or anaphthyl group. As preferred substituents on R₂₁₃, an alkyl group, analkoxyl group, an acyl group, a nitro group, a hydroxyl group, analkoxycarbonyl group, and a carboxyl group are exemplified.

R₂₁₄ and R₂₁₅ each represents a hydrogen atom, an alkyl group or acycloalkyl group.

Y₂₀₁ and Y₂₀₂ each represents an alkyl group, a cycloalkyl group, anaryl group, or a vinyl group.

X⁻ represents an anion of the organic acid represented by formula (I).

R₂₁₃ and R₂₁₄ may be bonded to each other to form a cyclic structure,R₂₁₄ and R₂₁₅ may be bonded to each other to form a cyclic structure,and Y₂₀₁ and Y₂₀₂ may be bonded to each other to form a cyclicstructure. These cyclic structures may contain an oxygen atom, a sulfuratom, an ester bond, and an amido bond. As the groups formed by bondingR₂₁₃ and R₂₁₄, R₂₁₄ and R₂₁₅, and Y₂₀₁ and Y₂₀₂, a butylene group, apentylene group, and the like can be exemplified.

The alkyl group represented by R₂₁₄, R₂₁₅, Y₂₀₁ and Y₂₀₂ is preferably astraight chain or branched alkyl group having from 1 to 20 carbon atoms.The alkyl group represented by Y₂₀₁ and Y₂₀₂ is preferably a 2-oxoalkylgroup having >C═O at the 2-position of the alkyl group, or analkoxycarbonylalkyl group (preferably an alkoxyl group having from 2 to20 carbon atoms), and more preferably a carboxyalkyl group.

The cycloalkyl group represented by R₂₁₄, R₂₁₅, Y₂₀₁ and Y₂₀₂ ispreferably a cycloalkyl group having from 3 to 20 carbon atoms.

Y₂₀₁ and Y₂₀₂ each preferably represents an alkyl group having 4 or morecarbon atoms, more preferably an alkyl group having from 4 to 6 carbonatoms, and still more preferably an alkyl group having from 4 to 12carbon atoms.

It is preferred that at least one of R₂₁₄ and R₂₁₅ represents an alkylgroup, and more preferably both R₂₁₄ and R₂₁₅ represent an alkyl group.

In formula (A2), R₂₀₄ and R₂₀₅ each represents an aryl group, an alkylgroup, or a cycloalkyl group.

X⁻ represents an anion of the organic acid represented by formula (I).

As the aryl group represented by R₂₀₄ and R₂₀₅, an aryl group consistingof hydrocarbon, and a heteroaryl group having a hetero atom, such as anitrogen atom, a sulfur atom, or an oxygen atom are exemplified. As thearyl groups consisting of hydrocarbon, a phenyl group and a naphthylgroup are preferred, and a phenyl group is more preferred. As theheteroaryl groups, e.g., a pyrrole group, an indole group, a carbazolegroup, a furan group, a thiophene group, etc., are exemplified, and anindole group is preferred.

The alkyl group represented by R₂₀₄ and R₂₀₅ may be either straightchain or branched, and preferably a straight chain or branched alkylgroup having from 1 to 10 carbon atoms, e.g., a methyl group, an ethylgroup, a propyl group, a butyl group, and a pentyl group can beexemplified.

The cycloalkyl group represented by R₂₀₄ and R₂₀₅ is preferably acycloalkyl group having from 3 to 10 carbon atoms, e.g., a cyclopentylgroup, a cyclohexyl group, and a norbonyl group can be exemplified.

R₂₀₄ and R₂₀₅ may have a substituent. As the substituents that R₂₀₄ andR₂₀₅ may have, e.g., an alkyl group (e.g., having from 1 to 15 carbonatoms), a cycloalkyl group (e.g., having from 3 to 15 carbon atoms), anaryl group (e.g., having from 6 to 15 carbon atoms), an alkoxyl group(e.g., having from 1 to 15 carbon atoms), a halogen atom, a hydroxylgroup, and a phenylthio group can be exemplified.

Compound (A) is preferably a compound represented by formula (A1), andmore preferably a compound represented by formula (A1a), (A1b) or (A1c).

The specific examples of the anionic parts in compound (A) are shownbelow, but the invention is not restricted thereto.

The specific examples of the cationic parts in compound (A) are shownbelow, but the invention is not restricted thereto.

The specific examples of compound (A) are shown in Table 1 below, butthe invention is not restricted thereto. TABLE 1 Compound (A) CationicPart Anionic Part A-1 I-1 X1 A-2 I-1 X2 A-3 I-2 X3 A-4 I-1 X4 A-5 I-1 X5A-6 I-1 X6 A-7 I-1 X7 A-8 I-1 X8 A-9 I-3 X9 A-10 I-1 X10 A-11 I-1 X11A-12 I-2 X12 A-13 I-4 X13 A-14 I-1 X14 A-15 I-1 X15 A-16 I-25 X16 A-17I-26 X17 A-18 I-27 X18 A-19 I-28 X19 A-20 I-29 X20 A-21 I-30 X21 A-22I-1 X22 A-23 I-26 X23 A-24 I-1 X24 A-25 I-1 X25 A-26 I-1 X26 A-27 I-1X27 A-28 I-1 X28 A-29 I-2 X29 A-30 I-1 X30 A-31 I-26 X31 A-32 I-2 X32A-33 I-1 X33 A-34 I-1 X34 A-35 I-1 X35 A-36 I-1 X36 A-37 I-25 X37 A-38I-1 X38 A-39 I-1 X39 A-40 I-1 X40 A-41 I-33 X41 A-42 I-26 X42 A-43 I-2X43 A-44 I-26 X44 A-45 I-1 X45 A-46 I-1 X46 A-47 I-11 X47 A-48 I-1 X48A-49 I-8 X49 A-50 I-1 X50 A-51 I-10 X51 A-52 I-2 X52 A-53 I-2 X53 A-54I-24 X54 A-55 I-1 X55 A-56 I-1 X56 A-57 I-4 X57 A-58 I-4 X58 A-59 I-1X59 A-60 I-25 X60 A-61 I-2 X61 A-62 I-26 X62 A-63 I-29 X63 A-64 I-1 X64A-65 I-31 X64 A-66 I-13 X65 A-67 I-1 X66 A-68 I-2 X67 A-69 I-31 X36 A-70I-31 X10 A-71 I-31 X45 A-72 I-2 X48 A-73 I-1 X68 A-74 I-1 X69 A-75 I-2X70 A-76 I-1 X71 A-77 I-2 X72 A-78 I-1 X73 A-79 I-1 X74 A-80 I-1 X75A-81 I-1 X76 A-82 I-1 X77 A-83 I-1 X78 A-84 I-1 X79 A-85 I-2 X74 A-86I-12 X74 A-87 I-31 X74 A-88 I-32 X74 A-89 I-2 X79 A-90 I-12 X79 A-91I-31 X79 A-92 I-32 X79 A-93 I-8 X74

Compound (A) can be easily synthesized from the compound represented byformula (I), or a lithium, sodium, or potassium salt of the compound,and hydroxide, bromide or chloride of iodonium or sulfonium according tothe salt exchange method disclosed in JP-T-11-501909 orJP-A-2003-246786.

The content of compound (A) in the photosensitive composition in theinvention is preferably from 0.1 to 20 mass % based on the solidscontent of the composition, and more preferably from 0.1 to 10 mass %.(In this specification, mass ratio is equal to weight ratio.)

[2] (B) A Compound Capable of Generating an Acid upon Irradiation withActinic Ray or Radiation:

It is preferred for the photosensitive composition in the invention tofurther contain a compound capable of generating an acid uponirradiation with actinic ray or radiation (hereinafter also referred toas “an acid generator usable in combination”) besides compound (A).

As acid generators usable in combination, photoinitiators ofphotocationic polymerization, photoinitiators of photoradicalpolymerization, photo-decoloring agents and photo-discoloring agents ofdyestuffs, well-known compounds capable of generating an acid uponirradiation with actinic ray or radiation that are used in micro-resistsand the like, and the mixtures of these compounds can be optionallyselected and used.

For example, diazonium salt, phosphonium salt, sulfonium salt, iodoniumsalt, imidosulfonate, oximesulfonate, diazodisulfone, disulfone, ando-nitrobenzylsulfonate are exemplified.

Further, compounds obtained by introducing a group or a compound capableof generating an acid upon irradiation with actinic ray or radiation tothe main chain or side chain of polymers, for example, the compoundsdisclosed in U.S. Pat. No. 3,849,137, German Patent 3,914,407,JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038,JP-A-63-163452, JP-A-62-153853, JP-A-63-146029, etc., can be used.

The compounds generating an acid by the action of lights as disclosed inU.S. Pat. No. 3,779,778, EP 126712, etc., can also be used.

As a preferred acid generator usable in combination, a compoundrepresented by the following formula (ZI), (ZII) or (ZIII) can beexemplified.

In formula (ZI), R₂₀₁, R₂₀₂ and R₂₀₃ each represents an organic group.

The number of carbon atoms of the organic groups represented by R₂₀₁,R₂₀₂ and R₂₀₃ is generally from 1 to 30, and preferably from 1 to 20.

Two of R₂₀₁, R₂₀₂ and R₂₀₃ may be bonded to each other to form a cyclicstructure, and an oxygen atom, a sulfur atom, an ester bond, an amidobond or a carbonyl group may be contained in the ring. As the groupformed by bonding two of R₂₀₁, R₂₀₂ and R₂₀₃, an alkylene group (e.g., abutylene group, a pentylene group) can be exemplified.

Z⁻ represents a non-nucleophilic anion.

The examples of the non-nucleophilic anions represented by Z⁻ include,e.g., a sulfonate anion, a carboxylate anion, a sulfonylimide anion, abis(alkylsulfonyl)imide anion, and a tris(alkylsulfonyl)methyl anion.

A non-nucleophilic anion is an anion having extremely low ability ofcausing a nucleophilic reaction and capable of restraining the agingdecomposition due to an intramolecular nucleophilic reaction, so thatthe aging stability of a resist can be improved with a non-nucleophilicanion.

As sulfonate anions, e.g., an aliphatic sulfonate anion, an aromaticsulfonate anion and a camphor sulfonate anion are exemplified.

As carboxylate anions, e.g., an aliphatic carboxylate anion, an aromaticcarboxylate anion and an aralkylcarboxylate anion are exemplified.

The aliphatic moiety in the aliphatic sulfonate anion may be an alkylgroup or a cycloalkyl group, preferably an alkyl group having from 1 to30 carbon atoms and a cycloalkyl group having from 3 to 30 carbon atoms,e.g., a methyl group, an ethyl group, a propyl group, an isopropylgroup, an n-butyl group, an isobutyl group, a sec-butyl group, a pentylgroup, a neopentyl group, a hexyl group, a heptyl group, an octyl group,a nonyl group, a decyl group, an undecyl group, a dodecyl group, atridecyl group, a tetradecyl group, a pentadecyl group, a hexadecylgroup, a heptadecyl group, an octadecyl group, a nonadecyl group, aneicosyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexylgroup, an adamantyl group, a norbonyl group, and a boronyl group areexemplified.

The aromatic group in the aromatic sulfonate anion is preferably an arylgroup having from 6 to 14 carbon atoms, e.g., a phenyl group, a tolylgroup, and a naphthyl group are exemplified.

The alkyl group, cycloalkyl group and aryl group in the aliphaticsulfonate anion and aromatic sulfonate anion may have a substituent. Asthe substituents of the alkyl group, cycloalkyl group and aryl group inthe aliphatic sulfonate anion and aromatic sulfonate anion, e.g., anitro group, a halogen atom (a fluorine atom, a chlorine atom, a bromineatom, and an iodine atom), a carboxyl group, a hydroxyl group, an aminogroup, a cyano group, an alkoxyl group (preferably having from 1 to 15carbon atoms), a cycloalkyl group (preferably having from 3 to 15 carbonatoms), an aryl group (preferably having from 6 to 14 carbon atoms), analkoxycarbonyl group (preferably having from 2 to 7 carbon atoms), anacyl group (preferably having from 2 to 12 carbon atoms), analkoxy-carbonyloxy group (preferably having from 2 to 7 carbon atoms),an alkylthio group (preferably having from 1 to 15 carbon atoms), analkylsulfonyl group (preferably having from 1 to 15 carbon atoms), analkyliminosulfonyl group (preferably having from 2 to 15 carbon atoms),an aryloxysulfonyl group (preferably having from 6 to 20 carbon atoms),an alkylaryloxysulfonyl group (preferably having from 7 to 20 carbonatoms), a cycloalkylaryloxysulfonyl group (preferably having from 5 to20 carbon atoms), and a cycloalkylalkyloxyalkyloxy group (preferablyhaving from 8 to 20 carbon atoms) are exemplified. As for the aryl groupand the cyclic structure of each group, an alkyl group (preferablyhaving from 1 to 15 carbon atoms) can be further exemplified as thesubstituent.

As the aliphatic moiety in the aliphatic carboxylate anion, the samealkyl group and cycloalkyl group as in the aliphatic sulfonate anion canbe exemplified.

As the aromatic group in an aromatic carboxylate anion, the same arylgroup as in the aromatic sulfonate anion can be exemplified.

As the aralkyl group in the aralkylcarboxylate anion, preferably anaralkyl group having from 6 to 12 carbon atoms, e.g., a benzyl group, aphenethyl group, a naphthylmethyl group, a naphthylethyl group, and anaphthylmethyl group can be exemplified.

The alkyl group, cycloalkyl group, aryl group and aralkyl group in thealiphatic carboxylate anion, aromatic carboxylate anion andaralkylcarboxylate anion may have a substituent. As the substituents ofthe alkyl group, cycloalkyl group, aryl group and aralkyl group in thealiphatic carboxylate anion, aromatic carboxylate anion andaralkylcarboxylate anion, e.g., the same halogen atom, alkyl group,cycloalkyl group, alkoxyl group and alkylthio group as in the aromaticsulfonate anion can be exemplified.

As the sulfonylimide anion, e.g., a saccharin anion can be exemplified.

The alkyl group in the bis(alkylsulfonyl)imide anion andtris(alkylsulfonyl)methyl anion is preferably an alkyl group having from1 to 5 carbon atoms, e.g., a methyl group, an ethyl group, a propylgroup, an isopropyl group, an n-butyl group, an isobutyl group, asec-butyl group, a pentyl group and a neopentyl group are exemplified.As the substituents on these alkyl groups, a halogen atom, an alkylgroup substituted with a halogen atom, an alkoxyl group, an alkylthiogroup, an alkyloxysulfonyl group, an aryloxysulfonyl group, and acycloalkylaryloxysulfonyl group can be exemplified, and an alkyl groupsubstituted with a fluorine atom is preferred.

As other non-nucleophilic anions, e.g., fluorinated phosphorus,fluorinated boron and fluorinated antimony can be exemplified.

As the non-nucleophilic anions represented by Z⁻, an aliphatic sulfonateanion in which the α-position of the sulfonic acid is substituted with afluorine atom, an aromatic sulfonate anion substituted with a fluorineatom or a group having a fluorine atom, a bis(alkylsulfonyl)imide anionin which the alkyl group is substituted with a fluorine atom, and atris(alkylsulfonyl)methide anion in which the alkyl group is substitutedwith a fluorine atom are preferred. Especially preferrednon-nucleophilic anions are an aliphatic perfluoro-sulfonate anionhaving from 4 to 8 carbon atoms, and a benzenesulfonate anion having afluorine atom, and still more preferred non-nucleophilic anions are anonafluorobutane-sulfonate anion, a perfluorooctanesulfonate anion, apenta-fluorobenzenesulfonate anion, and a3,5-bis(trifluoro-methyl)benzenesulfonate anion.

As the examples of the organic groups represented by R₂₀₁, R₂₀₂ andR₂₀₃, the corresponding groups in the later-described compoundsrepresented by formula (ZI-1), (ZI-2) or (ZI-3) can be exemplified.

The compound represented by formula (ZI) may be a compound having aplurality of structures represented by formula (ZI). For instance,compound (ZI) may be a compound having a structure that at least one ofR₂₀₁, R₂₀₂ and R₂₀₃ of the compound represented by formula (ZI) isbonded to at least one of R₂₀₁, R₂₀₂ and R₂₀₃ of another compoundrepresented by formula (ZI).

The following compounds (ZI-1), (ZI-2) and (ZI-3) can be exemplified asmore preferred components (ZI).

Compound (ZI-1) is an arylsulfonium compound that at least one of R₂₀₁to R₂₀₃ in formula (ZI) represents an aryl group, i.e., a compoundhaving arylsulfonium as a cation.

All of R₂₀₁ to R₂₀₃ of the arylsulfonium compound may be aryl groups, ora part of R₂₀₁ to R₂₀₃ may be an aryl group and the remainder may be analkyl group or a cycloalkyl group.

As the arylsulfonium compounds, e.g., a triarylsulfonium compound, adiarylalkylsulfonium compound, an aryldialkyl-sulfonium compound, adiarylcycloalkylsulfonium compound, and an aryldicycloalkylsulfoniumcompound are exemplified.

As the aryl groups of the arylsulfonium compound, a phenyl group and anaphthyl group are preferred, and the more preferred group is a phenylgroup. The aryl group may be an aryl group having a heterocyclicstructure having an oxygen atom, a nitrogen atom or a sulfur atom. Asthe aryl group having a heterocyclic structure, e.g., a pyrrole residue(a group formed by eliminating one hydrogen atom from pyrrole), a furanresidue (a group formed by eliminating one hydrogen atom from furan), athiophene residue (a group formed by eliminating one hydrogen atom fromthiophene), an indole residue (a group formed by eliminating onehydrogen atom from indole), a benzofuran residue (a group formed byeliminating one hydrogen atom from benzofuran), and a benzothiopheneresidue (a group formed by eliminating one hydrogen atom frombenzothiophene) can be exemplified. When the arylsulfonium compound hastwo or more aryl groups, these two or more aryl groups may be the sameor different.

As an alkyl group or a cycloalkyl group that the arylsulfonium compoundhas according to necessity, a straight chain or branched alkyl grouphaving from 1 to 15 carbon atoms and a cycloalkyl group having from 3 to15 carbon atoms are preferred, e.g., a methyl group, an ethyl group, apropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, acyclopropyl group, a cyclobutyl group and a cyclohexyl group can beexemplified.

The aryl group, alkyl group and cycloalkyl group represented by R₂₀₁,R₂₀₂ and R₂₀₃ may have a substituent and, e.g., an alkyl group (e.g.,having from 1 to 15 carbon atoms), a cycloalkyl group (e.g., having from3 to 15 carbon atoms), an aryl group (e.g., having from 6 to 14 carbonatoms), an alkoxyl group (e.g., having from 1 to 15 carbon atoms), ahalogen atom, a hydroxyl group, and a phenylthio group are exemplifiedas the substituents. The preferred substituents are a straight chain orbranched alkyl group having from 1 to 12 carbon atoms, a cycloalkylgroup having from 3 to 12 carbon atoms, and a straight chain, branchedor cyclic alkoxyl group having from 1 to 12 carbon atoms, and the mostpreferred substituents are an alkyl group having from 1 to 4 carbonatoms and an alkoxyl group having from 1 to 4 carbon atoms. Thesubstituent may be substituted on any one of three of R₂₀₁ to R₂₀₃, ormay be substituted on all of the three. When R₂₀₁, R₂₀₂ and R₂₀₃ eachrepresents an aryl group, it is preferred that the substituent besubstituted on the p-position of the aryl group.

Compound (ZI-2) is described below.

Compound (ZI-2) is a compound in the case where R₂₀₁, R₂₀₂ and R₂₀₃ informula (ZI) each represents an organic group not containing an aromaticring. The aromatic ring also includes an aromatic ring containing ahetero atom.

The organic groups not containing an aromatic ring represented by R₂₀₁to R₂₀₃ generally have from 1 to 30 carbon atoms, and preferably from 1to 20 carbon atoms.

R₂₀₁, R₂₀₂ and R₂₀₃ each preferably represents an alkyl group, acycloalkyl group, an allyl group, or a vinyl group, more preferably astraight chain or branched 2-oxoalkyl group, a 2-oxocycloalkyl group oran alkoxycarbonylmethyl group, and especially preferably a straight orbranched 2-oxoalkyl group.

The alkyl group and cycloalkyl group represented by R₂₀₁ to R₂₀₃ arepreferably a straight chain or branched alkyl group having from 1 to 10carbon atoms (e.g., a methyl group, an ethyl group, a propyl group, abutyl group, a pentyl group), and a cycloalkyl group having from 3 to 10carbon atoms (e.g., a cyclopentyl group, a cyclohexyl group, a norbonylgroup). The alkyl group is more preferably a 2-oxoalkyl group or analkoxycarbonylmethyl group. The cycloalkyl group is more preferably a2-oxocycloalkyl group.

The 2-oxoalkyl group may be either a straight chain or branched group,and a group having >C═O on the 2-position of the above alkyl group canbe exemplified as a preferred group.

The 2-oxocycloalkyl group is preferably a group having >C═O on the2-position of the above cycloalkyl group.

As the alkoxyl group in the alkoxycarbonylmethyl group, an alkoxyl grouppreferably having from 1 to 5 carbon atoms (e.g., a methoxy group, anethoxy group, a propoxy group, a butoxy group, a pentoxy group) can beexemplified.

R₂₀₁ to R₂₀₃ may further be substituted with a halogen atom, an alkoxylgroup (e.g., having from 1 to 5 carbon atoms), a hydroxyl group, a cyanogroup, or a nitro group.

Compound (ZI-3) is a compound represented by the following formula(ZI-3), which compound has a phenacyl-sulfonium salt structure.

In formula (ZI-3), R_(1c), R_(2c), R_(3c), R_(4c) and R_(5c) eachrepresents a hydrogen atom, an alkyl group, a cycloalkyl group, analkoxy group, or a halogen atom.

R_(6c) and R_(7c) each represents a hydrogen atom, an alkyl group or acycloalkyl group.

R_(x) and R_(y) each represents an alkyl group, a cycloalkyl group, anallyl group, or a vinyl group.

Any two or more of R_(1c) to R_(5c), R_(6c) and R_(7c), and R_(x) andR_(y) may be bonded to each other to form cyclic structures,respectively, and the cyclic structures may contain an oxygen atom, asulfur atom, an ester bond, or an amido bond. As the groups formed byany two or more of R_(1c) to R_(5c), R_(6c) and R_(7c), and R_(x) andR_(y), a butylene group, a pentylene group, etc., can be exemplified.

Z_(c) ⁻ represents a non-nucleophilic anion, and the samenon-nucleophilic anions as represented by X⁻ in formula (ZI) can beexemplified.

The alkyl groups represented by R_(1c) to R_(7c) may be either straightchain or branched, e.g., an alkyl group having from 1 to 20 carbonatoms, preferably a straight chain or branched alkyl group having from 1to 12 carbon atoms (e.g., a methyl group, an ethyl group, a straightchain or branched propyl group, a straight chain or branched butylgroup, a straight chain or branched pentyl group) can be exemplified. Asthe cycloalkyl groups represented by R_(1c) to R_(7c), a cycloalkylgroup having from 3 to 8 carbon atoms (e.g., a cyclopentyl group and acyclohexyl group) can be exemplified.

The alkoxyl groups represented by R_(1c) to R_(5c) may be any ofstraight chain, branched and cyclic, e.g., an alkoxyl group having from1 to 10 carbon atoms, preferably a straight chain or branched alkoxylgroup having from 1 to 5 carbon atoms (e.g., a methoxy group, an ethoxygroup, a straight chain or branched propoxy group, a straight chain orbranched butoxy group, a straight chain or branched pentoxy group), acyclic alkoxyl group having from 3 to 8 carbon atoms (e.g., acyclopentyloxy group, a cyclohexyloxy group) can be exemplified.

It is preferred that any of R_(1c) to R_(5c) represents a straight chainor branched alkyl group, a cycloalkyl group, or a straight chain,branched or cyclic alkoxyl group, it is more preferred that the sumtotal of the carbon atoms of R_(1c) to R_(5c) is from 2 to 15, by whichthe solubility in a solvent increases and generation of particles duringpreservation can be restrained.

As the alkyl group and cycloalkyl group represented by R_(x) and R_(y),the same alkyl groups and cycloalkyl groups represented by R_(1c) toR_(7c) can be exemplified, and a 2-oxoalkyl group, a 2-oxocycloalkylgroup and an alkoxycarbonylmethyl group are more preferred.

As the 2-oxoalkyl group and the 2-oxocycloalkyl group, groupshaving >C═O on the 2-position of the alkyl group and the cycloalkylgroup represented by R_(1c) to R_(7c) can be exemplified.

As the alkoxyl group of the alkoxycarbonylmethyl group, the same alkoxylgroups as those represented by R_(1c) and R_(5c) can be exemplified.

R_(x) and R_(y) each preferably represents an alkyl group or acycloalkyl group having 4 or more carbon atoms, more preferably 6 ormore carbon atoms, and still more preferably an alkyl group or acycloalkyl group having 8 or more carbon atoms.

In formulae (ZII) and (ZIII), R₂₀₄, R₂₀₅, R₂₀₆ and R₂₀₇ each representsan aryl group, an alkyl group or a cycloalkyl group.

The aryl group represented by R₂₀₄ to R₂₀₇ is preferably a phenyl groupor a naphthyl group, and more preferably a phenyl group. The aryl grouprepresented by R₂₀₄ to R₂₀₇ may be an aryl group having a heterocyclicstructure having an oxygen atom, a nitrogen atom or a sulfur atom. Asthe aryl group having a heterocyclic structure, e.g., a pyrrole residue(a group formed by eliminating one hydrogen atom from pyrrole), a furanresidue (a group formed by eliminating one hydrogen atom from furan), athiophene residue (a group formed by eliminating one hydrogen atom fromthiophene), an indole residue (a group formed by eliminating onehydrogen atom from indole), a benzofuran residue (a group formed byeliminating one hydrogen atom from benzofuran), and a benzothiopheneresidue (a group formed by eliminating one hydrogen atom frombenzothiophene) can be exemplified.

The alkyl group and the cycloalkyl group represented by R₂₀₄ to R₂₀₇ arepreferably a straight chain or branched alkyl group having from 1 to 10carbon atoms (e.g., a methyl group, an ethyl group, a propyl group, abutyl group, a pentyl group), and a cycloalkyl group having from 3 to 10carbon atoms (e.g., a cyclopentyl group, a cyclohexyl group, a norbonylgroup).

The aryl group, alkyl group and cycloalkyl group represented by R₂₀₄ toR₂₀₇ may have a substituent. As the substituents that the aryl group,alkyl group and cycloalkyl group represented by R₂₀₄ to R₂₀₇ may have,e.g., an alkyl group (e.g., having from 1 to 15 carbon atoms), acycloalkyl group (e.g., having from 3 to 15 carbon atoms), an aryl group(e.g., having from 6 to 15 carbon atoms), an alkoxyl group (e.g., havingfrom 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and aphenylthio group can be exemplified.

Z⁻ represents a non-nucleophilic anion, and the same non-nucleophilicanions as those represented by Z⁻ in formula (ZI) can be exemplified.

As the acid generators usable in combination, the compounds representedby the following formula (ZIV), (ZV) or (ZVI) can further beexemplified.

In formulae (ZIV), (ZV) and (ZVI), Ar³ and Ar⁴ each represents an arylgroup.

R₂₀₆, R₂₀₇ and R₂₀₈ each represents an alkyl group, a cycloalkyl groupor an aryl group.

A represents an alkylene group, an alkenylene group or an arylene group.

Of the acid generators usable in combination, more preferred compoundsare the compounds represented by formulae (ZI), (ZII) and (ZIII).

Further, as the acid generators usable in combination, a compoundgenerating an acid having one sulfonic acid group or an imido group ispreferred, a compound generating a monovalent perfluoroalkanesulfonicacid, a compound generating an aromatic sulfonic acid substituted with amonovalent fluorine atom or a group containing a fluorine atom, and acompound generating an imidic acid substituted with a monovalentfluorine atom or a group containing a fluorine atom are more preferred,and a sulfonium salt of a fluorine-substituted alkanesulfonic acid, afluorine-substituted benzenesulfonic acid, or a fluorine-substitutedimidic acid is still more preferred. As the acid generators usable incombination, a fluorine-substituted alkanesulfonic acid, afluorine-substituted benzenesulfonic acid, and fluorine-substitutedimidic acid each having pKa of−1 or less of generated acid areespecially preferred, by which sensitivity is improved.

The examples of especially preferred acid generators usable incombination are shown below.

The acid generators usable in combination can be used alone, or two ormore in combination.

The content of the acid generators usable in combination in aphotosensitive composition is preferably from 0.1 to 20 mass % based onthe total solids content of the photosensitive composition, morepreferably from 0.5 to 10 mass %, and still more preferably from 1 to 7mass %.

[3] (C) A Resin Capable of Decomposing by the Action of an Acid toIncrease Solubility in an Alkali Developing Solution (Referred to asalso Component (C)):

A resin capable of decomposing by the action of an acid to increasesolubility in an alkali developing solution for use in the positivephotosensitive composition in the invention is a resin having a groupdecomposable by the action of an acid (hereinafter referred to as “anacid-decomposable group”) on the main chain or side chain of the resin,or on both the main chain and side chain. A resin having a groupdecomposable by the action of an acid on the side chain is morepreferred.

A preferred acid-decomposable group is a group obtained by substitutingthe hydrogen atom of a —COOH group or an —OH group with a group capableof being desorbed by an acid.

An especially preferred acid-decomposable group in the invention is anacetal group or a tertiary ester group.

The parent resin in the case where the acid-decomposable group is bondedas the side chain is an alkali-soluble resin having an —OH group or a—COOH group on the side chain. For example, the later-describedalkali-soluble resins can be exemplified.

The alkali dissolution rate of these alkali-soluble resins is preferably170 Å/sec or more when measured using 0.261N tetramethylammoniumhydroxide (TMAH) at 23° C., especially preferably 330 Å/sec or more.

From this point of view, particularly preferred alkali-soluble resinsare o-, m-, p-poly(hydroxystyrene) and copolymers thereof, hydrogenatedpoly(hydroxystyrene), halogen- or alkyl-substitutedpoly(hydroxystyrene), a partially O-alkylated or O-acylated product ofpoly-(hydroxystyrene), styrene-hydroxystyrene copolymers,α-methylstyrene-hydroxystyrene copolymers, alkali-soluble resins havinga hydroxystyrene structure unit such as hydrogenated novolak resins,(meth)acrylic acid, and alkali-soluble resins containing a repeatingunit having a carboxyl group such as norbomenecarboxylic acid.

As repeating units having a preferred acid-decomposable group, e.g.,t-butoxycarbonyloxystyrene, 1-alkoxyethoxy-styrene, and (meth)acrylicacid tertiary alkyl ester are exemplified, and 2-alkyl-2-adamantyl(meth)acrylate and dialkyl(1-adamantyl)methyl (meth)acrylate are morepreferred.

Components (C) for use in the invention can be obtained, as disclosed inEP 254853, JP-A-2-25850, JP-A-3-223860 and JP-A-4-251259, by reacting analkali-soluble resin with the precursor of an acid-decomposable group,or copolymerizing an alkali-soluble resin monomer to which anacid-decomposable group is bonded with various monomers.

When the positive photosensitive composition of the invention isirradiated with KrF excimer laser beams, electron beams, X-rays, or highenergy rays of wavelength of 50 nm or lower (e.g., EUV), it is preferredfor a resin of component (C) to have a hydroxystyrene repeating unit,more preferably a copolymer of hydroxystyrene/hydroxystyrene protectedwith an acid-decomposable group, or hydroxystyrene/(meth)acrylic acidtertiary alkyl ester.

The specific examples of component (C) for use in the invention areshown below, but the invention is not restricted thereto.

In the above specific examples, tBu means a t-butyl group.

The content of an acid-decomposable group is expressed by B/(B+S),taking the number of the acid-decomposable groups in a resin as (B), andthe number of alkali-soluble groups not protected with acid-eliminablegroups as (S). The content is preferably from 0.01 to 0.7, morepreferably from 0.05 to 0.50, and still more preferably from 0.05 to0.40.

When the positive photosensitive composition in the invention isirradiated with ArF excimer laser beams, it is preferred that the resinof component (C) is a resin having a monocyclic or polycyclic alicyclichydrocarbon structure and capable of decomposing by the action of anacid to thereby increase the solubility in an alkali developingsolution.

As a resin having a monocyclic or polycyclic alicyclic hydrocarbonstructure and capable of decomposing by the action of an acid to therebyincrease the solubility in an alkali developing solution (hereinafteralso.referred to as “an alicyclic hydrocarbon acid-decomposable resin”),a resin containing at least one repeating unit selected from the groupconsisting of a repeating unit having a partial structure containingalicyclic hydrocarbon represented by any of the following formulae (pl)to (pV), and a repeating unit represented by the following formula(II-AB) is preferred.

In formulae (pI) to (pV), R₁₁ represents a methyl group, an ethyl group,an n-propyl group, an isopropyl group, an n-butyl group, an isobutylgroup, or a sec-butyl group; and Z represents an atomic group necessaryto form a cycloalkyl group together with a carbon atom.

R₁₂, R₁₃, R₁₄, R₁₅ and R₁₆ each represents a straight chain or branchedalkyl group, or a cycloalkyl group, provided that at least one of R₁₂ toR₁₄, or either R₁₅ or R₁₆ represents a cycloalkyl group.

R₁₇, R₁₈, R₁₉, R₂₀ and R₂₁ each represents a hydrogen atom, a straightchain or branched alkyl group or a cycloalkyl group, provided that atleast one of R₁₇ to R₂₁ represents a cycloalkyl group, and either R₁₉ orR₂₁ represents a straight chain or branched alkyl group or a cycloalkylgroup.

R₂₂, R₂₃, R₂₄ and R₂₅ each represents a hydrogen atom, a straight chainor branched alkyl group or a cycloalkyl group, provided that at leastone of R₂₂ to R₂₅ represents a cycloalkyl group, and R₂₃ and R₂₄ may bebonded to each other to form a ring.

In formula (II-AB), R₁₁′ and R₁₂′ each represents a hydrogen atom, acyano group, a halogen atom, or an alkyl group.

Z′ contains bonded two carbon atoms (C-C) and represents an atomic groupto form an alicyclic structure.

Formula (II-AB) is more preferably represented by the following formula(II-AB1) or (II-AB2).

In formulae (II-AB1) and (II-AB2), R₁₃′, R₁₄′, R₁₅′ and R₁₆′ eachrepresents a hydrogen atom, a halogen atom, a cyano group, —COOH,—COOR₅, a group decomposable by the action of an acid, —C(═O)—X—A′—R₁₇′,an alkyl group, or a cycloalkyl group. At least two of R₁₃′ to R₁₆′ maybe bonded to form a ring.

R₅ represents an alkyl group, a cycloalkyl group, or a group having alactone structure.

X represents an oxygen atom, a sulfur atom, —NH—, —NHSO₂— or —NHSO₂NH—.

A′ represents a single bond or a divalent linking group.

R₁₇′ represents —COOH, —COOR₅, —CN, a hydroxyl group, an alkoxyl group,—CO—NH—R₆, —CO—NH—SO₂—R₆, or a group having a lactone structure.

R₆ represents an alkyl group or a cycloalkyl group. n represents 0 or 1.

The alkyl group represented by R₁₂ to R₂₅ in formulae (pI) to (pV) ispreferably a straight chain or branched alkyl group having from 1 to 4carbon atoms, e.g., a methyl group, an ethyl group, an n-propyl group,an isopropyl group, an n-butyl group, an isobutyl group, and a sec-butylgroup are exemplified.

The cycloalkyl groups represented by R₁₁ to R₂₅ or the cycloalkyl groupformed by Z and carbon atoms may be monocyclic or polycyclic.Specifically, groups having a monocyclic, bicyclic, tricyclic ortetracyclic structure having 5 or more carbon atoms can be exemplified.The number of carbon atoms of the groups is preferably from 6 to 30, andparticularly preferably from 7 to 25.

As preferred cycloalkyl groups, an adamantyl group, a noradamantylgroup, a decalin residue, a tricyclodecanyl group, a tetracyclododecanylgroup, a norbomyl group, a cedrol group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a cyclooctyl group, acyclodecanyl group, and a cyclododecanyl group can be exemplified. Morepreferred cycloalkyl groups are an adamantyl group, a norbomyl group, acyclohexyl group, a cyclopentyl group, a tetracyclododecanyl group, anda tricyclodecanyl group.

These alkyl groups and cycloalkyl groups may have further substituents.As further substituents of these alkyl groups and cycloalkyl groups, analkyl group (having from 1 to 4 carbon atoms), a halogen atom, ahydroxyl group, an alkoxyl group (having from 1 to 4 carbon atoms), acarboxyl group, and an alkoxycarbonyl group (having from 2 to 6 carbonatoms) can be exemplified. As substituents that these alkyl group,alkoxyl group and alkoxycarbonyl group may further have, a hydroxylgroup, a halogen atom and an alkoxyl group can be exemplified.

The structures represented by formulae (pI) to (pV) in the resin can beused for the protection of alkali-soluble groups. As the alkali-solublegroups, various groups well known in this technical field can beexemplified.

Specifically, the structures in which the hydrogen atoms of carboxylicacid group, a sulfonic acid group, a phenol group and a thiol group aresubstituted with the structures represented by formulae (pI) to (pV) areexemplified, and preferably the structures in which the hydrogen atomsof carboxylic acid group and a sulfonic acid group are substituted withthe structures represented by formulae (pI) to (pV) are exemplified.

As the repeating unit having the alkali-soluble group protected with thestructure represented by any of the above formulae (pI) to (pV), arepeating unit represented by the following formula (pA) is preferred.

In formula (pA), R represents a hydrogen atom, a halogen atom, or astraight chain or branched alkyl group having from 1 to 4 carbon atoms,and a plurality of R's may be the same or different.

A represents a single group or the combination of two or more groupsselected from the group consisting of a single bond, an alkylene group,an ether group, a thioether group, a carbonyl group, an ester group, anamido group, a sulfonamido group, a urethane group, and a urea group. Asingle bond is preferred.

R_(p1) represents a group represented by any of formulae (pI) to (pVI).

The repeating unit represented by (pA) is most preferably a repeatingunit by 2-alkyl-2-adamantyl (meth)acrylate anddialkyl(1-adamantyl)methyl (meth)acrylate.

The specific examples of the repeating units represented by formula (pA)are shown below, but the invention is not restricted thereto. (In theformulae, Rx represents H, CH₃, CF₃, CH₂OH, Rxa and Rxb each representsan alkyl from 1 to 4 carbon atoms.)

As the halogen atoms represented by R₁₁′ and R₁₂′ in formula (II-AB), achlorine atom, a fluorine atom and an iodine atom are exemplified.

As the alkyl groups represented by R₁₁′ and R₁₂′, straight chain orbranched alkyl groups having from 1 to 10 carbon atoms are exemplified.

The atomic group represented by Z′ to form an alicyclic structure is anatomic group to form a repeating unit having an alicyclic hydrocarbonstructure, which may have a substituent, and an atomic group to form arepeating unit having a bridged alicyclic hydrocarbon structure ispreferred above all.

As the skeleton of alicyclic hydrocarbon formed, the same alicyclichydrocarbon groups as represented by R₁₂ to R₂₅ in formulae (pl) to (pV)are exemplified.

The skeleton of the alicyclic hydrocarbon structure may have asubstituent, and as the substituents, the groups represented by R₁₃′ toR₁₆′ in formula (II-AB1) or (II-AB2) can be exemplified.

In the alicyclic hydrocarbon-based acid-decomposable resin in theinvention, a group capable of decomposing by the action of an acid canbe contained in at least one repeating unit of a repeating unit having apartial structure containing alicyclic hydrocarbon represented by any offormulae (pI) to (pV), a repeating unit represented by formula (II-AB),and a repeating unit of the later-described copolymer component.

Various substituents of R₁₃′ to R₁₆′ in formula (II-AB1) or (II-AB2) canalso be used as the substituents of the atomic group to form analicyclic hydrocarbon structure in formula (II-AB), or atomic group Z toform a bridged alicyclic hydrocarbon structure.

The specific examples of the repeating units represented by formula(II-AB1) or (II-AB2) are shown below, but the invention is notrestricted thereto.

The alicyclic hydrocarbon-based acid-decomposable resin in the inventionpreferably contains a repeating unit having a group having a lactonestructure. As the group having a lactone structure, any group having alactone structure can be used, but preferably groups having 5- to7-membered ring lactone structures, and 5- to 7-membered ring lactonestructures condensed with other ring structures in the form of forming abicyclo structure or a spiro structure are preferred. As the grouphaving a lactone structure, a group having a lactone structurerepresented by any of the following formulae (LC1-1) to (LC1-16) is morepreferred. A group having a lactone structure may be directly bonded tothe main chain of a repeating unit. Preferred lactone structures are(LC1-1), (LC1-4) (LC1-5), (LC1-6), (LC1-13) and (LC1-14). By the use ofa specific lactone structure, line edge roughness and development defectare bettered.

A lactone structure moiety may have or may not have a substituent (Rb₂).As preferred substituent (Rb₂), an alkyl group having from 1 to 8 carbonatoms, a cycloalkyl group having from 3 to 7 carbon atoms, an alkoxylgroup having from 1 to 8 carbon atoms, an alkoxycarbonyl group havingfrom 1 to 8 carbon atoms, a carboxyl group, a halogen atom, a hydroxylgroup, a cyano group, and an acid-decomposable group are exemplified. n₂represents an integer of from 0 to 4. When n₂ is 2 or more, a pluralityof Rb₂ may be the same or different, and a plurality of Rb₂ may bebonded to each other to form a ring.

As the repeating units having a group having a lactone structurerepresented by any of formulae (LC1-1) to (LC1-16), a repeating unit inwhich at least one of R₁₃′ to R₁₆′ in formula (II-AB1) or (II-AB2) is agroup having a lactone structure represented by any of formulae (LC1-1)to (LC1-16) (for example, R₅ of —COOR₅ is a group having a lactonestructure represented by any of formulae (LC1-1) to (LC1-16)), or arepeating unit represented by the following formula (AI) can beexemplified.

In formula (AI), Rb₀ represents a hydrogen atom, a halogen atom, or analkyl group having from 1 to 4 carbon atoms. As the preferredsubstituents that the alkyl group represented by Rb₀ may have, ahydroxyl group and a halogen atom are exemplified.

As the halogen atom represented by Rb₀, a fluorine atom, a chlorineatom, a bromine atom and an iodine atom can be exemplified.

Rb₀ preferably represents a hydrogen atom or a methyl group.

Ab represents a single bond, an alkylene group, a divalent linking grouphaving a monocyclic or polycyclic alicyclic hydrocarbon structure, anether group, an ester group, a carbonyl group, a carboxyl group, or adivalent linking group combining these groups.

Ab preferably represents a single bond or a linking group represented by—Ab₁—CO₂—. Ab₁ represents a straight chain or branched alkylene group,or a monocyclic or polycyclic cycloalkylene group, and preferably amethylene group, an ethylene group, a cyclohexyl group, an adamantylgroup, or a norbomyl group.

V represents a group having a lactone structure represented by any offormulae (LC1-1) to (LC1-16).

Repeating units having a lactone structure generally have opticalisomers, and any optical isomer may be used. One kind of optical isomermay be used alone, or a plurality of optical isomers may be used asmixture. When one kind of optical isomer is mainly used, the opticalpurity (ee) of the optical isomer is preferably 90 or more, and morepreferably 95 or more.

The specific examples of repeating units having a group having a lactonestructure are shown below, but the invention is not limited thereto.(In the Formulae, Rx Represents H, CH₃, CH₂OH or CF₃.)

(In the Formulae, Rx Represents H, CH₃, CH₂OH or CF₃.)

(In the Formulae, Rx Represents H, CH₃, CH₂OH or CF₃.)

It is preferred for the alicyclic hydrocarbon-based acid-decomposableresin of the invention to have a repeating unit having a group having analicyclic hydrocarbon structure substituted with a polar group, by whichadhesion with a substrate and affinity with a developing solution areimproved. As the alicyclic hydrocarbon structure of the alicyclichydrocarbon structure substituted with a polar group, an adamnantylgroup, a diamantyl group, and a norbornane group are preferred. As thepolar group, a hydroxyl group and a cyano group are preferred. As thegroup having the alicyclic hydrocarbon structure substituted with apolar group, a group represented by any of the following formulae (VIIa)to (VIId) is preferred.

In formula (VIIa) to (VIIc), R_(2c), R_(3c) and R_(4c) each represents ahydrogen atom, a hydroxyl group, or a cyano group, provided that atleast one of R_(2c), R_(3c) and R_(4c) represents a hydroxyl group or acyano group. Preferably one or two of R_(2c), R_(3c) and R_(4c)represent a hydroxyl group and the remainder represent a hydrogen atom.In formula (VIIa), more preferably two of R_(2c), R_(3c) and R_(4c)represent a hydroxyl group and the remainder represents a hydrogen atom.

As the repeating unit having a group represented by any of formulae(VIIa) to (VIId), a repeating unit in which at least one of R₁₃′ to R₁₆′in formula (II-AB1) or (II-AB2) is a group represented by any offormulae (VIIa) to (VIId) (for example, R₅ of —COOR₅ is a grouprepresented by any of formulae (VIIa) to (VIId)), or a repeating unitrepresented by any of the following formulae (AIIa) to (AIId) can beexemplified.

In formulae (AIIa) to (AIId), R_(1c) represents a hydrogen atom, amethyl group, a trifluoromethyl group, or a hydroxymethyl group.

The specific examples of the repeating units represented by formulae(AIIa) to (AIId) are shown below, but the invention is not restrictedthereto.

The alicyclic hydrocarbon-based acid-decomposable resin in the inventionmay have a repeating unit represented by the following formula (VIII).

In formula (VIII), Z₂ represents —O— or —N(R₄₁)—. R₄₁ represents ahydrogen atom, a hydroxyl group, an alkyl group, or —OSO₂—R₄₂. R₄₂represents an alkyl group, a cycloalkyl group, or a camphor residue. Thealkyl group represented by R₄₁ and R₄₂ may be substituted with a halogenatom (preferably a fluorine atom) and the like.

As the specific examples of the repeating units represented by formula(VIII), the following compounds are exemplified, but the invention isnot restricted thereto.

It is preferred for the alicyclic hydrocarbon-based acid-decomposableresin in the invention to have a repeating unit having an alkali-solublegroup, and it is more preferred to have a repeating unit having acarboxyl group, by which the resolution in the use for contact hole isenhanced. As the repeating units having a carboxyl group, a repeatingunit having a carboxyl group directly bonded to the main chain of aresin such as a repeating unit by acrylic acid or methacrylic acid, arepeating unit having a carboxyl group bonded to the main chain of aresin via a linking group, and a repeating unit having a carboxyl groupintroduced to the terminals of a polymer chain by polymerization with apolymerization initiator having an alkali-soluble group and a chaintransfer agent are exemplified, and any of these repeating units ispreferably used. Linking groups may have a monocyclic or polycyclichydrocarbon structure. The repeating unit by acrylic acid or methacrylicacid is especially preferred.

The alicyclic hydrocarbon-based acid-decomposable resin in the inventionmay further have a repeating unit having one to three groups representedby the following formula (F1), by which line edge roughness property isimproved.

In formula (F1), R₅₀, R₅₁, R₅₂, R₅₃, R₅₄ and R₅₅ each represents ahydrogen atom, a fluorine atom, or an alkyl group, provided that atleast one of R₅₀ to R₅₅ represents a fluorine atom, or an alkyl group inwhich at least one hydrogen atom is substituted with a fluorine atom.

Rxa represents a hydrogen atom or an organic group (preferably anacid-decomposable protective group, an alkyl group, a cycloalkyl group,an acyl group, or an alkoxycarbonyl group).

The alkyl group represented by R₅₀ to R₅₅ may be substituted with ahalogen atom, e.g., a fluorine atom, or a cyano group, and preferably analkyl group having from 1 to 3 carbon atoms, e.g., a methyl group and atrifluoromethyl group can be exemplified.

It is preferred that all of R₅₀ to R₅₅ represent a fluorine atom.

As the organic group represented by Rxa, an acid-decomposable protectivegroup, and an alkyl group, a cycloalkyl group, an acyl group, analkylcarbonyl group, an alkoxycarbonyl group, an alkoxycarbonylmethylgroup, an alkoxymethyl group, and a 1-alkoxyethyl group, each of whichmay have a substituent, are preferred.

The repeating unit having the group represented by formula (F1) ispreferably a repeating unit represented by the following formula (F2).

In formula (F2), Rx represents a hydrogen atom, a halogen atom, or analkyl group having from 1 to 4 carbon atoms. As preferred substituentsthat the alkyl group represented by Rx may have, a hydroxyl group and ahalogen atom are exemplified.

Fa represents a single bond or a straight chain or branched alkylenegroup, and preferably a single bond.

Fb represents a monocyclic or polycyclic hydrocarbon group.

Fc represents a single bond or a straight chain or branched alkylenegroup, and preferably a single bond or a methylene group.

F₁ represents a group represented by formula (F1).

P₁ is from 1 to 3.

As the cyclic hydrocarbon group represented by Fb, a cyclopentyl group,a cyclohexyl group, or a norbomyl group is preferred.

The specific examples of the repeating units having the grouprepresented by formula (F1) are shown below, but the invention is notrestricted thereto.

The alicyclic hydrocarbon-based acid-decomposable resin in the inventionmay further contain a repeating unit having an alicyclic hydrocarbonstructure and not showing acid decomposability, by containing such arepeating unit, the elution of low molecular weight components from aresist film into an immersion liquid can be reduced at the time ofimmersion exposure. As such repeating units, e.g., 1-adamantyl(meth)acrylate, tricyclodecanyl (meth)acrylate, and cyclohexyl(meth)acrylate, are exemplified.

The alicyclic hydrocarbon-based acid-decomposable resin in the inventioncan contain various kinds of repeating structural units, besides theabove repeating structural units, for the purpose of the adjustments ofdry etching resistance, aptitude for standard developing solutions,adhesion to a substrate, resist profile, and further, general requisitecharacteristics of resists, e.g., resolution, heat resistance andsensitivity.

As these repeating structural units,-the repeating structural unitscorresponding to the monomers shown below can be exemplified, but theinvention is not restricted thereto.

By containing such various repeating structural units, fine adjustmentof performances required of the alicyclic hydrocarbon-basedacid-decomposable resin, in particular the following performances,becomes possible, that is,

-   (1) Solubility in a coating solvent,-   (2) A film-forming property (a glass transition point),-   (3) Alkali developability,-   (4) Decrease of layer thickness (hydrophobic-hydrophilic property,    selection of an alkali-soluble group),-   (5) Adhesion of an unexposed area to a substrate, and-   (6) Dry etching resistance.

The examples of such monomers include compounds having one additionpolymerizable unsaturated bond selected from acrylic esters, methacrylicesters, acrylamides, methacryl-amides, allyl compounds, vinyl ethers,vinyl esters, etc.

In addition to the aforementioned compounds, addition polymerizableunsaturated compounds copolymerizable with the monomers corresponding tothe above various repeating structural units may be used forcopolymerization.

In the alicyclic hydrocarbon-based acid-decomposable resin, the molarratio of the content of each repeating structural unit is arbitrarilyset to adjust dry etching resistance and aptitude for standarddeveloping solutions of a resist, adhesion to a substrate, and resistprofile, in addition, general requisite characteristics of a resist,e.g., resolution, heat resistance and sensitivity.

As preferred embodiments of the alicyclic hydrocarbon-basedacid-decomposable resin in the invention, the following resins areexemplified.

-   (1) A resin containing a repeating unit having a partial structure    containing the alicyclic hydrocarbon represented by any of formulae    (pI) to (pV) (a side chain type), preferably a resin containing a    (meth)acrylate repeating unit having the structure of any of    formulae (pI) to (pV);-   (2) A resin containing a repeating unit represented by formula    (II-AB) (a main chain type); however, the following is further    exemplified as embodiment (2):-   (3) A resin containing a repeating unit represented by formula    (II-AB), a maleic anhydride derivative and a (meth)acrylate    structure (a hybrid type).

In the alicyclic hydrocarbon-based acid-decomposable resin, the contentof a repeating unit having an acid- decomposable group is preferablyfrom 10 to 60 mol% in the total repeating structural units, morepreferably from 20 to 50 mol %, and still more preferably from 25 to 40mol %.

In the alicyclic hydrocarbon-based acid-decomposable resin, the contentof a repeating unit having a partial structure containing the alicyclichydrocarbon represented by any of formulae (pI) to (pV) is preferablyfrom 20 to 70 mol % in the total repeating structural units, morepreferably from 20 to 50 mol %, and still more preferably from 25 to 40mol %.

In the alicyclic hydrocarbon-based acid-decomposable resin, the contentof a repeating unit represented by formula (II-AB) is preferably from 10to 60 mol % in the total repeating structural units, more preferablyfrom 15 to 55 mol %, and still more preferably from 20 to 50 mol %.

The content of the repeating structural units on the basis of themonomers of further copolymerization components in the resin can also beoptionally set according to the desired resist performances, and thecontent is generally preferably 99 mol % or less to the total mol numberof the repeating structural units having a partial structure containingthe alicyclic hydrocarbon represented by any of formulae (pI) to (pV)and the repeating units represented by formula (II-AB), more preferably90 mol % or less, and still more preferably 80 mol % or less.

When the composition in the invention is for ArF exposure, it ispreferred that the resin does not have an aromatic group from the aspectof the transparency to ArF rays.

The alicyclic hydrocarbon-based acid-decomposable resin for use in theinvention is preferably such that all the repeating units consist of(meth)acrylate repeating units. In this case, any of the following casescan be used, that is, a case where all the repeating units consist ofmethacrylate, a case where all the repeating units consist of acrylate,and a case where the repeating units consist of mixture of methacrylateand acrylate, but it is preferred that acrylate repeating units accountfor 50 mol % or less of all the repeating units. More preferred resinsare ternary copolymers comprising from 20 to 50 mol % of repeating unitshaving a partial structure containing the alicyclic hydrocarbonrepresented by any of formulae (pI) to (pV), from 20 to 50 mol % ofrepeating units having a lactone structure, and from 5 to 30 mol % ofrepeating units having an alicyclic hydrocarbon structure substitutedwith a polar group, and quaternary copolymers further containing from 0to 20 mol % of other repeating units.

Especially preferred resins are ternary copolymers comprising from 20 to50 mol % of a repeating unit having an acid-decomposable grouprepresented by any of the following formulae (ARA-1) to (ARA-5), from 20to 50 mol % of a repeating unit having a lactone group represented byany of the following formulae (ARL-1) to (ARL-6), and from 5 to 30 mol %of a repeating unit having an alicyclic hydrocarbon structuresubstituted with a polar group represented by any of the followingformulae (ARH-1) to (ARH-3), and quaternary copolymers furthercontaining from 5 to 20 mol % of a repeating unit having a carboxylgroup or a structure represented by formula (F1), and a repeating unithaving an alicyclic hydrocarbon structure and not showing aciddecomposability.

In the above formulae, Rxy₁ represents a hydrogen atom or a methylgroup.

Rxa₁ and Rxb₁ each represents a methyl group or an ethyl group.

The alicyclic hydrocarbon-based acid-decomposable resins for use in theinvention can be synthesized according to ordinary methods (e.g.,radical polymerization). For instance, as ordinary methods, a batchpolymerization method of dissolving a monomer and an initiator in asolvent and heating the solution to perform polymerization, and adropping polymerization method of adding a solution of a monomer and aninitiator to a heated solvent over 1 to 10 hours by dropping areexemplified, and dropping polymerization is preferred. As reactionsolvents, ethers, e.g., tetrahydrofuran, 1,4-dioxane, and diisopropylether, ketones, e.g., methyl ethyl ketone and methyl isobutyl ketone, anester solvent, e.g., ethyl acetate, amide solvents, e.g.,dimethylformamide and dimethyacetamide, and the later-described solventscapable of dissolving the composition of the invention, e.g., propyelneglycol monomethyl ether acetate, propylene glycol monomethyl ether, andcyclohexanone are exemplified. It is more preferred to use the samesolvent in polymerization as the solvent used in the resist compositionin the invention, by which the generation of particles duringpreservation can be restrained.

It is preferred to perform polymerization reaction in the atmosphere ofinert gas such as nitrogen or argon. Polymerization is initiated withcommercially available radical polymerization initiators (e.g., azoinitiators, peroxide and the like). As radical polymerizationinitiators, azo initiators are preferred, and azo initiators having anester group, a cyano group, or a carboxyl group are preferred. Aspreferred initiators, azobisisobutyronitrile,azobis-dimethylvaleronitrile, dimethyl-2,2′-azibis(2-methyl-propionate),etc., are exemplified. Initiators are added additionally or dividedly,if desired, and after termination of the reaction, the reaction productis put into a solvent and an objective polymer is recovered as powder ora solid state. The reaction concentration is from 5 to 50 mass %, andpreferably from 10 to 30 mass %. The reaction temperature is generallyfrom 10 to 150° C., preferably from 30 to 120° C., and more preferablyfrom 60 to 100° C.

When the photosensitive composition according to the invention is usedin the upper layer resist of a multilayer resist, it is preferred thatthe resin of component (C) should have a silicon atom.

As resins having a silicon atom and capable of decomposing by the actionof an acid to thereby increase the solubility in an alkali developingsolution, resins having a silicon atom at least on one side of the mainchain and the side chain can be used. As resins having a siloxanestructure on the side chain of resins, copolymer of, e.g., an olefinmonomer having a silicon atom on the side chain, and a (meth)acrylicacid monomer having maleic anhydride and an acid decomposable group onthe side chain.

As resins having a silicon atom, resins having a trialkylsilyl structureand a monocyclic or polycyclic siloxane structure are preferred, resinshaving repeating units having the structures represented by any of thefollowing formulae (SS-1) to (SS-4) are more preferred, and(meth)acrylic ester repeating units having the structures represented byany of formulae (SS-1) to (SS-4), vinyl repeating units, and allylrepeating units are still more preferred.

In formulae (SS-1) to (SS-4), Rs represents an alkyl group having from 1to 5 carbon atoms, preferably a methyl group or an ethyl group.

It is preferred that resins having silicon atoms have two or more kindsof different repeating units having silicon atoms, resins having both(Sa) repeating unit having from 1 to 4 silicon atoms and (Sb) repeatingunit having from 5 to 10 silicon atoms are more preferred, and resinshaving at least one repeating unit having a structure represented by anyof formulae (SS-1) to (SS-3) and a repeating unit having a structurerepresented by formula (SS-4) are still more preferred.

When the positive photosensitive composition of the invention isirradiated with F₂ excimer laser beams, the resin of component (C) ispreferably a resin having a structure wherein the main chain and/or sidechain of the polymer skeleton are substituted with fluorine atoms andcapable of decomposing by the action of an acid to increase thesolubility in an alkali developing solution (hereinafter also referredto as “a fluorine-based acid-decomposable resin), the resin is morepreferably a resin having a hydroxyl group the 1-position of which issubstituted with a fluorine atom or a fluoroalkyl group, or having agroup obtained by protecting a hydroxyl group the 1-position of which issubstituted with a fluorine atom or a fluoroalkyl group with anacid-decomposable group. The especially preferred resin is a resinhaving a hexafluoro-2-propanol structure, or a resin having a structurethat the hydroxyl group of hexafluoro-2-propanol is protected with anacid-decomposable group. By the incorporation of fluorine atoms, thetransparency to the far ultraviolet rays, in particular to F₂ ray (157nm) can be improved.

As the fluorine-based acid- decomposable resin, resins having at leastone repeating unit represented by any of the following formulae (FA) to(FG) are preferably exemplified.

In the above formulae, R₁₀₀, R₁₀₁, R₁₀₂ and R₁₀₃ each represents ahydrogen atom, a fluorine atom, an alkyl group, or an aryl group.

R₁₀₄ and R₁₀₆ each represents a hydrogen atom, a fluorine atom, or analkyl group, and at least one of R₁₀₄ and R₁₀₆ represents a fluorineatom or a fluoroalkyl group. Preferably both R₁₀₄ and R₁₀₆ represent atrifluoromethyl group.

R₁₀₅ represents a hydrogen atom, an alkyl group, a cycloalkyl group, anacyl group, an alkoxycarbonyl group, or a group decomposable by theaction of an acid.

A₁ represents a single bond, a divalent linking group, e.g., an alkylenegroup, a cycloalkylene group, an alkenylene group, an arylene group,—OCO—, —COO—, —CON(R₂₄)—, or a linking group containing a plurality ofthese groups. R₂₄ represents a hydrogen atom or an alkyl group.

R₁₀₇ and R₁₀₈ each represents a hydrogen atom, a halogen atom, an alkylgroup, an alkoxyl group, an alkoxycarbonyl group, or a groupdecomposable by the action of an acid.

R₁₀₉ represents a hydrogen atom, an alkyl group, a cycloalkyl group, ora group decomposable by the action of an acid. b represents 0, 1 or 2.

Further, R₁₀₀ and R₁₀₁ in formulae (FA) and (FC) may form a ring throughan alkylene group (having from 1 to 5 carbon atoms) which may besubstituted with a fluorine atom.

The repeating units represented by formulae (FA) to (FG) have at least1, preferably 3 or more, fluorine atoms per one repeating unit.

In formulae (FA) to (FG), the alkyl group is an alkyl group having from1 to 8 carbon atoms, specifically, a methyl group, an ethyl group, apropyl group, an n-butyl group, a sec-butyl group, a hexyl group, a2-ethylhexyl group, and an octyl group are preferably exemplified.

The cycloalkyl group may be monocyclic or polycyclic. As the monocycliccycloalkyl groups, those having from 3 to 8 carbon atoms, e.g., acyclopropyl group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, and a cyclooctyl group are preferably exemplified. Asthe polycyclic groups, preferably those having from 6 to 20 carbonatoms, e.g., an adamantyl group, a norbomyl group, an isoboronyl group,a camphanyl group, a dicyclopentyl group, an a-pinel group, atricyclodecanyl group, a tetracyclododecyl group, and an androstanylgroup are exemplified. However, the carbon atoms in the monocyclic orpolycyclic cycloalkyl groups may be substituted with hetero atoms suchas an oxygen atom, etc.

The fluoroalkyl group is a fluoroalkyl group having from 1 to 12 carbonatoms, and specifically a trifluoromethyl group, a perfluoroethyl group,a perfluoropropyl group, a perfluoro-butyl group, a perfluorohexylgroup, a perfluorooctyl group, a perfluorooctylethyl group, and aperfluorododecyl group are preferably exemplified.

The aryl group is an aryl group having from 6 to 15 carbon atoms, andspecifically a phenyl group, a tolyl group, a dimethylphenyl group, a2,4,6-trimethylphenyl group, a naphthyl group, an anthryl group and a9,10-dimethoxyanthryl group are preferably exemplified.

The alkoxyl group is an alkoxyl group having from 1 to 8 carbon atoms,and specifically a methoxy group, an ethoxy group, an n-propoxy group,an isopropoxy group, a butoxy group, a pentoxy group, an allyloxy group,and an octoxy group are preferably exemplified.

The acyl group is an acyl group having from 1 to 10 carbon atoms, andspecifically a formyl group, an acetyl group, a propanoyl group, abutanoyl group, a pivaloyl group, an octanoyl group, and a benzoyl groupare preferably exemplified.

As the alkoxycarbonyl group, an i-propoxycarbonyl group, at-butoxycarbonyl group, a t-amyloxycarbonyl group, and a1-methyl-1-cyclohexyloxycarbonyl group, preferably a secondary, and morepreferably a tertiary alkoxycarbonyl group are exemplified.

As the halogen atom, e.g., a fluorine atom, a chlorine atom, a bromineatom and an iodine atom are exemplified.

As the alkylene group, preferably an alkylene group having from 1 to 8carbon atoms, e.g., a methylene group, an ethylene group, a propylenegroup, a butylene group, a hexylene group, and an octylene group areexemplified.

As the alkenylene group, preferably an alkenylene group having from 2 to6 carbon atoms, e.g., an ethenylene group, a propenylene group and abutenylene group are exemplified.

As the cycloalkylene group, preferably a cycloalkylene group having from5 to 8 carbon atoms, e.g., a cyclopentylene group and a cyclohexylenegroup are exemplified.

As the arylene group, preferably an arylene group having from 6 to 15carbon atoms, e.g., a phenylene group, a tolylene group and anaphthylene group are exemplified.

These groups may have a substituent, and the examples of thesubstituents include groups having active hydrogen, e.g., an alkylgroup, a cycloalkyl group, an aryl group, an amino group, an amidogroup, a ureido group, a urethane group, a hydroxyl group, and acarboxyl group, a halogen atom (e.g., a fluorine atom, a chlorine atom,a bromine atom, and an iodine atom), an alkoxyl group (e.g., a methoxygroup, an ethoxy group, a propoxy group, a butoxy group), a thioethergroup, an acyl group (e.g., an acetyl group, a propanoyl group, abenzoyl group), an acyloxy group (e.g., an acetoxy group, a propanoyloxygroup, a benzoyloxy group), an alkoxycarbonyl group (e.g., amethoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonylgroup), a cyano group, and a nitro group are exemplified.

Here, as the alkyl, cycloalkyl and aryl groups, those described aboveare exemplified, but the alkyl group may further be substituted with afluorine atom or a cycloalkyl group.

As the groups capable of decomposing by the action of an acid toincrease the solubility in an alkali developing solution contained inthe fluorine-based acid-decomposable resins, e.g., —O—C(R₃₆)(R₃₇)(R₃₈),—O—C(R₃₆)(R₃₇)(OR₃₉), —O—COO—C(R₃₆)(R₃₇)(R₃₈),—O—C(R₀₁)(R₀₂)COO—C(R₃₆)(R₃₇)(R₃₈), —COO—C(R₃₆)(R₃₇)(R₃₈), and—COO—C(R₃₆)(R₃₇)(OR₃₉) can be exemplified.

R₃₆, R₃₇, R₃₈ and R₃₉ each represents an alkyl group, a cycloalkylgroup, an aryl group, an aralkyl group, or an alkenyl group; R₀₁ and R₀₂each represents a hydrogen atom, an alkyl group, a cycloalkyl group, analkenyl group (e.g., a vinyl group, an allyl group, a butenyl group, acyclohexenyl group), an aralkyl group (e.g., a benzyl group, a phenethylgroup, a naphthylmethyl group), or an aryl group.

The preferred specific examples of the groups include the ether groupsor the ester groups of tertiary alkyl groups such as a t-butyl group, at-amyl group, a 1-alkyl-1-cyclohexyl group, a 2-alkyl-2-adamantyl group,a 2-adamantyl-2-propyl group, and a 2-(4-methylcyclohexyl)-2-propylgroup, acetal groups or acetal ester groups such as a 1-alkoxy-1-ethoxygroup and a tetrahydropyranyl group, a t-alkylcarbonate group and at-alkylcarbonylmethoxy group.

The specific examples of the repeating units represented by formulae(FA) to (FG) are shown below, but the invention is not restrictedthereto.

The total content of the repeating units represented by formulae (FA) to(FG) is generally from 10 to 80 mol % to all the repeating unitsconstituting the resin, preferably from 30 to 70 mol %, and morepreferably from 35 to 65 mol %.

For the purpose of further improving the performances of the resist ofthe invention, the fluorine-based acid- decomposable resins may furtherbe copolymerized with other polymerizable monomers in addition to theabove repeating structural units.

As the usable copolymerizable monomers, compounds having one additionpolymerizable unsaturated bond selected from acrylic esters,acrylamides, methacrylic esters, methacryl- amides, allyl compounds,vinyl ethers, vinyl esters, styrens, and crotonic esters other thandescribed above are exemplified.

It is preferred that these fluorine-based acid-decomposable resinscontain other repeating units as the copolymerization components besidesthe above repeating units having fluorine atoms from the points ofimproving dry etching resistance, adjusting alkali solubility, andimproving adhesion with substrates. Preferred other repeating units areas follows.

1) The repeating units having an alicyclic hydrocarbon structurerepresented by any of formulae (pI) to (pVI) and formula (II-AB).Specifically the above exemplified repeating units 1 to 23 and repeatingunits [II-1] to [II-32] shown above. Preferably repeating units 1 to 23,wherein R_(x) represents CF₃.

2) The repeating units having a lactone structure represented by formula(Lc) and any of formulae (V-1) to (V-5). Specifically theabove-exemplified repeating units, in particular, the above-exemplifiedrepeating units represented by formula (Lc) and formulae (V-1) to (V-4).

3) The repeating units derived from the vinyl compounds having maleicanhydride, vinyl ether or a cyano group represented by the followingformula (XV), (XVI) or (XVII). Specifically repeating units (C-1) to(C-15) shown below. These repeating units may or may not contain afluorine atom.

In the above formulae, R₄₁ represents an alkyl group, a cycloalkylgroup, an aralkyl group, or an aryl group, and the alkyl grouprepresented by R₄₁ may be substituted with an aryl group.

R₄₂ represents a hydrogen atom, a halogen atom, a cyano group, or analkyl group.

A₅ represents a single bond, a divalent alkylene group, alkenylenegroup, cycloalkylene group, or arylene group, or —O—CO—R₂₂—, —CO—O—R₂₃—,or —CO—N(R₂₄) —R₂₅—.

R₂₂, R₂₃ and R₂₅, which may be the same or different, each represents asingle bond, or a divalent alkylene group, alkenylene group,cycloalkylene group or arylene group which may have an ether group, anester group, an amido group, a urethane group or a ureido group.

R₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, anaralkyl group, or an aryl group.

Here, as the examples of the substituents, the same groups as thesubstituents in formulae (FA) to (FG) can be exemplified.

The specific examples of the repeating structural units represented byformulae (XV) to (XVII) are shown below, but the invention is notrestricted thereto.

The total amount of the repeating units represented by any of formulae(XV) to (XVII) and other repeating units is generally from 0 to 70 mol %to the total repeating units constituting the resin, preferably from 10to 60 mol %, and more preferably from 20 to 50 mol %.

The fluorine-based acid-decomposable resins may contain anacid-decomposable group in any repeating unit.

The content of a repeating unit having an acid decomposable group ispreferably from 10 to 70 mol % to the total repeating units, morepreferably from 20 to 60 mol %, and still more preferably from 30 to 60mol %.

The fluorine-based acid-decomposable resins can be synthesized byradical polymerization almost similar to the synthesis of alicyclichydrocarbon-based acid-decomposable resins.

The weight average molecular weight of the resin of component (C) ispreferably from 2,000 to 200,000 as the polystyrene equivalent by theGPC method. By making the weight average molecular weight 2,000 or more,heat resistance and dry etching resistance can be improved, and bymaking the weight average molecular weight 200,000 or less,developability can be improved, and film-forming property can beheightened, since the viscosity becomes low. The weight averagemolecular weight is more preferably from 5,000 to 50,000, and still morepreferably from 7,000 to 30,000. By the adjustment of the molecularweight, it is possible to reconcile the heat resistance of thecomposition, resolution, development failure and the like. The degree ofdispersion of molecular weight (Mw/Mn) of the resin of component (C) ispreferably from 1.0 to 3.0, more preferably from 1.2 to 2.5, and stillmore preferably from 1.2 to 1.6. By the adjustment of the degree ofdispersion to a proper range, the performance of line edge roughness canbe increased.

In the positive photosensitive composition in the invention, theproportion of the resin of component (C) of the invention in the entirecomposition is preferably from 40 to 99.99 mass % in the total solidscontent, more preferably from 50 to 99 mass %, and still more preferablyfrom 80 to 96 mass %.

[4] (D) A Dissolution Inhibiting Compound Capable of Decomposing by theAction of an Acid to Increase Solubility in an Alkali DevelopingSolution Having a Molecular Weight of 3,000 or Less (Hereinafter alsoReferred to as “Component (D)” or “Dissolution Inhibiting Compound”):

As (D) the dissolution inhibiting compound capable of decomposing by theaction of an acid to thereby increase the solubility in an alkalideveloping solution having a molecular weight of 3,000 or less,alicyclic or aliphatic compounds containing an acid-decomposable group,such as cholic acid derivatives containing an acid-decomposable groupdescribed in Proceeding of SPIE, 2724, 355 (1996) are preferred so asnot to reduce the permeability to lights of 220 nm or less. Asacid-decomposable groups and alicyclic structures, the same as thosedescribed above in the alicyclic hydrocarbon-based acid-decomposableresin are exemplified.

When the photosensitive composition of the invention is exposed with aKrF excimer laser or irradiated with electron beams, a phenolic compoundhaving a structure that the phenolic hydroxyl group is substituted withan acid-decomposable group is preferably used. As the phenoliccompounds, compounds having from 1 to 9 phenolic skeletons arepreferred, and those having from 2 to 6 are more preferred.

The molecular weight of the dissolution-inhibiting compound in theinvention is 3,000 or less, preferably from 300 to 3,000, and morepreferably from 500 to 2,500.

The addition amount of the dissolution-inhibiting compound is preferablyfrom 3 to 50 mass % based on the solids content of the photosensitivecomposition, and more preferably from 5 to 40 mass %.

The specific examples of the dissolution-inhibiting compounds are shownbelow, but the invention is not restricted thereto.

[5] (E) A Resin Soluble in an Alkali Developing Solution (Hereinafteralso Referred to as “Component (E)” or “Alkali-Soluble Resin”):

The alkali dissolution rate of alkali-soluble resins is preferably 20Å/sec or more when measured with 0.261 N tetramethylammonium hydroxide(TMAH) at 23° C., and especially preferably 200 Å/sec or more.

As alkali-soluble resins for use in the invention, e.g., novolak resins,hydrogenated novolak resins, acetone-pyrogallol resins,o-polyhydroxystyrene, m-polyhydroxy-styrene, p-polyhydroxystyrene,hydrogenated polyhydroxy-styrene, halogen- or alkyl-substitutedpolyhydroxystyrene, hydroxystyrene-N-substituted maleimide copolymers,o/p- and m/p-hydroxystyrene copolymers, partially O-alkylated productsof the hydroxyl group of polyhydroxystyrene (e.g., from 5 to 30 mol %0-methylated, O-(1-methoxy)ethylated, O-(1-ethoxy)ethylated,O-2-tetrahydropyranylated, and O-(t-butoxycarbonyl)methylated products),or partially O-acylated products (e.g., from 5 to 30 mol % o-acetylatedand O-(t-butoxy)carbonylated products), styrene-maleic anhydridecopolymers, styrene-hydroxystyrene copolymers,α-methylstyrene-hydroxystyrene copolymers, carboxyl group-containingmethacrylic resins and derivatives thereof, and polyvinyl alcoholderivatives can be exemplified, but the invention is not limited tothese resins.

Particularly preferred alkali-soluble resins are novolak resins,o-polyhydroxystyrene, m-polyhydroxystyrene p-polyhydroxystyrene,copolymers of them, alkyl-substituted polyhydroxystyrene, partiallyO-alkylated or O-acylated products of polyhydroxystyrene,styrene-hydroxystyrene copolymers, and α-methylstyrene-hydroxystyrenecopolymers.

The novolak resins can be obtained by addition condensation to aldehydeswith the prescribed monomers as main components in the presence of acidcatalysts.

The weight average molecular weight of alkali-soluble resins is 2,000 ormore, preferably from 5,000 to 200,000, and more preferably from 5,000to 100,000.

Here, the weight average molecular weight is defined as the polystyreneequivalent by gel permeation chromatography.

Alkali-soluble resins (E) in the invention may be used in combination oftwo kinds or more.

The use amount of alkali-soluble resins is from 40 to 97 mass % based onthe total solids content of the photosensitive composition, andpreferably from 60 to 90 mass %.

[6] (F) An Acid Crosslinking Agent Capable of Crosslinking with theAlkali-Soluble Resin by the Action of an Acid (hereinafter also Referredto as “Component (F)” or “a Crosslinking Agent”):

A crosslinking agent is used in the negative photosensitive compositionof the invention.

Every compound capable of crosslinking the resins soluble in an alkalideveloping solution by the action of an acid can be used as crosslinkingagents, but the following (1) to (3) are preferably used.

-   (1) Hydroxymethyl body, alkoxymethyl body and acyloxymethyl body of    phenol derivatives-   (2) Compounds having an N-hydroxymethyl group, an N-alkoxy- methyl    group or an N-acyloxymethyl group-   (3) Compounds having an epoxy group

As the alkoxymethyl groups, those ‘having’ 6 or less carbon atoms, andas the acyloxymethyl groups, those having 6 or less carbon atoms arepreferred.

Of these crosslinking agents, particularly preferred compounds are shownbelow.

In the above formulae, L₁ to L₈, which may be the same or different,each represents a hydrogen atom, a hydroxymethyl group, a methoxymethylgroup, an ethoxymethyl group, or an alkyl group having from 1 to 6carbon atoms.

Crosslinking agents are used generally in proportion of from 3 to 70mass % in the solids content of the photosensitive composition, andpreferably from 5 to 50 mass %. Other components:

[7] (G) A Basic Compound:

For decreasing the fluctuation of performances during the period of timefrom exposure to heating, it is preferred for the photosensitivecomposition of the invention to contain (G) a basic compound.

As the preferred structures of basic compounds, the structuresrepresented by any of the following formulae (A) to (E) can beexemplified.

In formula (A), R₂₅₀, R₂₅₁ and R₂₅₂ each represents a hydrogen atom, analkyl group having from 1 to 20 carbon atoms, a cycloalkyl group havingfrom 3 to 20 carbon atoms, or an aryl group having from 6 to 20 carbonatoms, and R₂₅₀ and R₂₅₁ may be bonded to each other to form a ring.These groups may have a substituent, and as the alkyl group andcycloalkyl group having a substituent, an aminoalkyl group having from 1to 20 carbon atoms or an aminocycloalkyl group having from 3 to 20carbon atoms, a hydroxyalkyl group having from 1 to 20 carbon atoms or ahydroxycycloalkyl group having from 3 to 20 carbon atoms are preferred.

These groups may contain an oxygen atom, a sulfur atom or a nitrogenatom in the alkyl chain.

In formula (E), R₂₅₃, R₂₅₄, R₂₅₅ and R₂₅₆ each represents an alkyl grouphaving from 1 to 6 carbon atoms, or a cycloalkyl group having from 3 to6 carbon atoms.

As the preferred examples of basic compounds, guanidine,aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine,aminoalkylmorpholine, and piperidine can be exemplified, and thesecompounds may have a substituent. As further preferred compounds,compounds having an imidazole structure, a diazabicyclo structure, anonium hydroxide structure, an onium carboxylate structure, atrialkylamine structure, an aniline structure, or a pyridine structure,alkylamine derivatives having a hydroxyl group and/or an ether bond, andaniline derivatives having a hydroxyl group and/or an ether bond can beexemplified.

As the compounds having an imidazole structure, imidazole,2,4,5-triphenylimidazole, and benzimidazole can be exemplified. As thecompounds having a diazabicyclo structure,1,4-diazabicyclo[2.2.2]octane, 1,5-diazabicyclo[4.3.0]non-5-ane, and1,8-diazabicyclo[5.4.0]undeca-7-ene can be exemplified. As the compoundshaving an onium hydroxide structure, triarylsulfonium hydroxide,phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkylgroup, specifically triphenylsulfonium hydroxide,tris(t-butyl-phenyl)sulfonium hydroxide, bis(t-butylphenyl)iodoniumhydroxide, phenacylthiophenium hydroxide, and 2-oxopropyl-thiopheniumhydroxide can be exemplified. The compounds having an onium carboxylatestructure are compounds having an onium hydroxide structure in which theanionic part is carboxylated, e.g., acetate, adamantane-1-carboxylate,and perfluoroalkyl carboxylate are exemplified. As the compounds havinga trialkylamine structure, tri(n-butyl)amine and tri(n-octyl)amine canbe exemplified. As the aniline compounds, 2,6-diisopropylaniline andN,N-dimethylaniline can be exemplified. As the alkylamine derivativeshaving a hydroxyl group and/or an ether bond, ethanolamine,diethanol-amine, triethanolamine, and tris(methoxyethoxyethyl)amine canbe exemplified. As the aniline derivatives having a hydroxyl groupand/or an ether bond, N,N-bis(hydroxyethyl)-aniline can be exemplified.

These basic compounds are used alone or in combination of two or more.However, when the use amount of component (B) is 0.05 mass % or more, abasic compound may not be used. When a basic compound is used, the useamount of the basic compound is generally from 0.001 to 10 mass % basedon the solids content of the photosensitive composition, and preferablyfrom 0.01 to 5 mass %. For obtaining a sufficient addition effect, theaddition amount is preferably 0.001 mass % or more, and in view ofsensitivity and the developability of a non-exposed area, the additionamount is preferably 10 mass % or less.

[8] (H) Surfactant:

It is preferred for the photosensitive composition in the invention tofurther contain a surfactant, and it is more preferred to contain eitherone, or two or more, of fluorine and/or silicon surfactants (a fluorinesurfactant, a silicon surfactant, a surfactant containing both afluorine atom and a silicon atom).

By containing a surfactant, it becomes possible for the photosensitivecomposition in the invention to provide a resist pattern excellent insensitivity and resolution, and low in defects in adhesion anddevelopment in using an exposure light source of 250 nm or lower, inparticular, 220 nm or lower.

These fluorine and/or silicon surfactants are disclosed, e.g., inJP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950,JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988,JP-A-2002-277862, U.S. Pat. Nos. 5,405,720, 5,360,692, 5,529,881,5,296,330, 5,436,098, 5,576,143, 5,294,511 and 5,824,451. Thecommercially available surfactants shown below can also be used as theyare.

As the commercially available fluorine or silicon surfactants usable inthe invention, e.g., Eftop EF301 and EF303 (manufactured by Shin-AkitaKasei Co., Ltd.), Fluorad FC430, 431 and 4430 (manufactured by Sumitomo3M Limited), Megafac F171, F173, F176, F189, F113, F110, F177, F120, andR08 (manufactured by Dainippon Ink and Chemicals Inc.), Sarfron S-382,SC 101, 102, 103, 104, 105 and 106 (manufactured by ASAHI GLASS CO.,LTD.), Troy Sol S-366 (manufactured by Troy Chemical Co., Ltd.), GF-300and GF-150 (manufactured by TOAGOSEI CO., LTD.), Sarfron S-393(manufactured by SEIMI CHEMICAL CO., LTD.), Eftop EF121, EF122A, EF122B,RF122C, EF125M, EF135M, EF351, 352, EF801, EF802, and EF601(manufactured by JEMCO INC.), PF636, PF656, PF6320 and PF6520(manufactured by OMNOVA), and FTX-204D, 208G, 218G, 230G, 204D, 208D,212D, 218, and 222D (manufactured by NEOS) are exemplified. In addition,polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co.,Ltd.) can also be used as a silicon surfactant.

In addition to these known surfactants as exemplified above, surfactantsusing polymers having fluoro-aliphatic groups derived fromfluoro-aliphatic compounds manufactured by a telomerization method (alsocalled a telomer method) or an oligomerization method (also called anoligomer method) can be used. The fluoro-aliphatic compounds can besynthesized by the method disclosed in JP-A-2002-90991.

As the polymers having fluoro-aliphatic groups, copolymers of monomershaving fluoro-aliphatic groups and (poly(oxyalkylene)) acrylate and/or(poly(oxyalkylene)) methacrylate are preferred, and they may bedistributed at random or block copolymerized. As the poly(oxyalkylene)groups, a poly(oxyethylene) group, a poly(oxypropylene) group, and apoly(oxybutylene) group are exemplified. Further, the polymers may beunits having alkylenes different in chain length in the same chainlength, such as a block combination of poly(oxyethylene and oxypropyleneand oxyethylene), and a block combination of poly(oxyethylene andoxypropylene). In addition, copolymers of monomers havingfluoro-aliphatic groups and poly(oxyalkylene) acrylate (or methacrylate)may be not only bipolymers but also terpolymers or higher polymersobtained by copolymerization of monomers having different two or morekinds of fluoro-aliphatic groups or different two or more kinds ofpoly(oxyalkylene) acrylates (or methacrylates) at the same time.

For example, as commercially available surfactants, Megafac F178, F470,F473, F475, F476 and F472 (manufactured by Dainippon Ink and ChemicalsInc.) can be exemplified. Further, copolymers of acrylate (ormethacrylate) having a C₆F₁₃ group and poly(oxyalkylene) acrylate (ormethacrylate), and copolymers of acrylate (or methacrylate) having aC₃F₇ group, poly(oxyethylene) acrylate (or methacrylate), andpoly(oxy-propylene) acrylate (or methacrylate) are exemplified.

In the invention, surfactants other than fluorine and/or siliconsurfactants can also be used. Specifically, nonionic surfactants, suchas polyoxyethylene alkyl ethers, e.g., polyoxyethylene lauryl ether,polyoxyethylene stearyl ether, polyoxyethylene cetyl ether,polyoxyethylene oleyl ether, etc., polyoxyethylene alkylallyl ether,e.g., polyoxyethylene octylphenol ether, polyoxyethylene nonylphenolether, etc., polyoxyethylene-polyoxypropylene block copolymers, sorbitanfatty acid esters, e.g., sorbitan monolaurate, sorbitan monopalmitate,sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitantristearate, etc., and polyoxyethylene sorbitan fatty acid esters, e.g.,polyoxy-ethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate, polyoxyethylene sorbitan tristearate, etc., can beexemplified.

These surfactants may be used alone or may be used in combination ofsome kinds.

The use amount of surfactants is preferably in proportion of from 0.01to 10 mass % to the total amount of the positive resist composition(excluding solvents), and more preferably from 0.1 to 5 mass %.

[9] (I) Organic Solvent:

The above components of the photosensitive composition of the inventionare dissolved in a prescribed organic solvent.

As the organic solvents usable in the invention, ethylene dichloride,cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methylethyl ketone, ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl etheracetate, propylene glycol monomethyl ether, propylene glycol monomethylether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate,methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethylpyruvate, propyl pyruvate, N,N-dimethylformamide, dimethyl sulfoxide,N-methylpyrrolidone, and tetrahydrofuiran are exemplified.

(Ia) Ketone Solvents:

Solvents containing at least a ketone structure are preferably used inthe invention.

As the solvents containing a ketone structure, chain-like ketonesolvents and cyclic ketone solvents are exemplified, and those havingfrom 5 to 8 carbon atoms are preferred for capable of obtaining goodcoating property.

As the chain-like ketone solvents, e.g., 2-heptanone, methyl ethylketone, methyl isobutyl ketone, etc., are exemplified, and 2-heptanoneis preferred.

As the cyclic ketone solvents, e.g., cyclopentanone,3-methyl-2-cyclopentanone, cyclohexanone, 2-methylcyclo-hexanone,2,6-dimethylcyclohexanone, cycloheptanone, cyclooctanone, isophorone,etc., are exemplified, and cyclohexanone and cycloheptanone arepreferred.

It is preferred that the solvents having a ketone structure are usedalone, or as mixed solvents with other solvents. As the solvents to bemixed (combined use solvents), propylene glycol monoalkyl ethercarboxylate, alkyl lactate, propylene glycol monoalkyl ether, alkylalkoxypropionate, lactone compounds, etc., can be exemplified.

As the propylene glycol monoalkyl ether carboxylate, e.g., propyleneglycol monomethyl ether acetate, propylene glycol monomethyl etherpropionate, propylene glycol monoethyl ether acetate, etc., can beexemplified.

As the alkyl lactate, e.g., methyl lactate, ethyl lactate, etc., can beexemplified.

As the propylene glycol monoalkyl ether, e.g., propylene glycolmonomethyl ether and propylene glycol monoethyl ether, etc., can beexemplified.

As the alkyl alkoxypropionate, e.g., methyl methoxy- propionate, ethylmethoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate,etc., can be exemplified.

As the lactone compounds, e.g., γ-butyrolactone, etc., can beexemplified.

As preferred combined use solvent, propylene glycol monoalkyl ethercarboxylate, alkyl lactate and propylene glycol monoalkyl ether can beexemplified, and as more preferred combined use solvent, propyleneglycol monomethyl ether acetate can be exemplified.

By the use of mixed solvents of ketone solvents and combined usesolvents, substrate adhesion, developability and DOF are improved.

The ratio of the ketone solvent and the combined use solvent (massratio) is preferably from 10/90 to 95/5, more preferably from 20/80 to80/20, and still more preferably from 30/70 to 70/30.

In view of heightening uniform film thickness and resistance todevelopment failure, high boiling point solvents having a boiling pointof 200° C. or higher, e.g., ethylene carbonate, propylene carbonate,etc., may be mixed.

The addition amount of these high boiling point solvents is generallyfrom 0.1 to 15 mass % in all the solvents, preferably from 0.5 to 10mass %, and more preferably from 1 to 5 mass %.

In the invention, a photosensitive composition having solids contentconcentration of generally from 3 to 25 mass %, preferably from 5 to 22mass %, and more preferably from 5 to 15 mass % is prepared with asingle solvent, preferably two or more solvents. Other additives:

If necessary, dyes, plasticizers, surfactants other than the surfactantsof component (H), photosensitizers, and compounds for expediting thedissolution of composition in a developing solution may be further addedto the photosensitive composition in the present invention.

Compounds for expediting dissolution in a developing solution that canbe used in the invention are low molecular weight compounds having amolecular weight of 1,000 or less and having two or more phenolic OHgroups or one or more carboxyl groups. When carboxyl groups arecontained, alicyclic or aliphatic compounds are preferred.

The preferred addition amount of these dissolution acceleratingcompounds is preferably from 2 to 50 mass % based on the resin ofcomponent (C) or the resin of component (E), and more preferably from 5to 30 mass %. The amount is preferably 50 mass % or less in the point ofrestraint of development residue and prevention of pattern deformationin development.

These phenolic compounds having a molecular weight of 1,000 or less canbe easily synthesized with referring to the methods disclosed, e.g., inJP-A-4-122938, JP-A-2-28531, U.S. Pat. No. 4,916,210, and EP 219294.

As the specific examples of the alicyclic or aliphatic compounds havinga carboxyl group, carboxylic acid derivatives having a steroidstructure, e.g., cholic acid, deoxycholic acid, and lithocholic acid,adamantanecarboxylic acid derivatives, adamantanedicarboxylic acid,cyclohexanecarboxylic acid, and cyclohexanedicarboxylic acid areexemplified, but the invention is not restricted to these compounds.

Pattern Forming Method:

The photosensitive composition in the invention is used by dissolvingeach of the above components in a prescribed organic solvent, preferablydissolving in a mixed solvent as described above, and coating thesolution on a prescribed support as follows.

For example, the photosensitive composition is coated on a substratesuch as the one used in the manufacture of precision integrated circuitelement (e.g., silicon/silicon dioxide coating) by an appropriatecoating method with a spinner or a coater, and dried, to thereby form aphotosensitive film.

The photosensitive film is irradiated with actinic ray or radiationthrough a prescribed mask, preferably subjected to baking (heating), andthen development. Thus, a good pattern can be obtained.

At the time of irradiation with actinic ray or radiation, exposure(immersion exposure) may be performed by filling a liquid (an immersionmedium) having higher refractive index than that of air between aphotosensitive film and a lens, by which resolution can be raised.

As actinic rays or radiation, infrared rays, visible rays, ultravioletrays, far ultraviolet rays, X-rays and electron beams can beexemplified, and preferably far ultraviolet rays of wavelengths of 250nm or less, and more preferably 220 nm or less. Specifically, a KrFexcimer laser (248 nm), an ArF excimer laser (193 nm), an F₂ excimerlaser (157 nm), X-rays and electron beams are exemplified, and ArFexcimer lasers, F₂ excimer lasers, EUV (13 nm), and electron beams arepreferred.

Immersion Exposure:

When the photosensitive composition in the invention is subjected toimmersion exposure, it is preferred that the photosensitive compositionis used in a thickness of from 30 to 250 nm in view of the improvementof resolution, and more preferably a thickness of from 30 to 100 nm.Such a desired thickness can be realized by setting the concentration ofsolids content in the photosensitive composition in a proper range andgiving appropriate viscosity to thereby improve the coating property andfilm forming property.

The concentration of all the solids content in the photosensitivecomposition is generally from 1 to 10 mass %, more preferably from 1 to8 mass %, and still more preferably from 1.0 to 6.0 mass %.

When the photosensitive composition in the invention is subjected toimmersion exposure, the photosensitive composition is used by dissolvingeach of the above components in a prescribed organic solvent, preferablyin a mixed solvent as described above, and coating the solution on aprescribed support as follows.

That is, the photosensitive composition is coated on a substrate such asthe one used in the production of precision integrated circuit elements(e.g., silicon/silicon dioxide coating) by an appropriate coating methodwith a spinner or a coater in an arbitrary thickness (generally from 30to 500 nm). After coating, if necessary, a resist film is washed withthe immersion liquid. The washing time is generally from 5 seconds to 5minutes.

Subsequently, the coated resist is dried by spin or bake to form aresist film, and the resist film formed is subjected to exposure(immersion exposure) for pattern formation through a mask via animmersion liquid. For example, exposure is performed in the state offilling an immersion liquid between a resist film and an optical lens.The exposure dose can be optionally set, but is generally from 1 to 100mJ/cm². After exposure, if necessary, the resist film is washed with theimmersion liquid. The washing time is generally from 5 seconds to 5minutes. After that, the resist film is preferably subjected to spinor/and bake, development and rinsing, whereby a good pattern can beobtained. It is preferred to perform bake, and the temperature of bakeis generally from 30 to 300° C. The time from exposure to bake processis preferably shorter from the viewpoint of PED.

The exposure rays here are far ultraviolet rays of wavelengths ofpreferably 250 nm or less, and more preferably 220 nm or less.Specifically, a KrF excimer laser (248 nm), an ArF excimer laser (193nm), an F₂ excimer laser (157 nm), and X-rays are exemplified.

Incidentally, the variation of performances of a resist at the time whensubjected to immersion exposure is thought to be resulting from thecontact of a resist surface with an immersion liquid.

An immersion liquid for use in immersion exposure is described below.

An immersion liquid for use in immersion exposure preferably has atemperature coefficient of refractive index as small as possible so asto be transparent to the exposure wavelength and to hold the distortionof an optical image reflected on the resist at the minimum. Inparticular, when the exposure light source is an ArF excimer laser(wavelength: 193 nm), it is preferred to use water as the immersionliquid for easiness of availability and capable of handling easily, inaddition to the above points.

It is also possible to use a medium having a refractive index of 1.5 ormore for capable of improving the refractive index. The medium may be anaqueous solution or an organic solvent.

When water is used as the immersion liquid, to reduce the surfacetension of water and to increase the surface activity, a trace amount ofadditive (a liquid) that does not dissolve the resist layer on a waferand has a negligible influence on the optical coating of the undersideof a lens element may be added. As such additives, aliphatic alcoholshaving a refractive index almost equal to the refractive index of waterare preferred, specifically methyl alcohol, ethyl alcohol and isopropylalcohol are exemplified. By adding an alcohol having a refractive indexalmost equal to that of water, even if the alcohol component in water isevaporated and the concentration of the content is changed, therefractive index variation of the liquid as a whole can be madeextremely small. On the other hand, when impurities opaque to the lightof 193 nm or substances largely different from water in a refractiveindex are mixed, these substances bring about the distortion of anoptical image reflected on the resist. Accordingly the water to be usedis preferably distilled water. Further, pure water filtered through anion exchange filter may be used.

The electric resistance of water is preferably 18.3 MΩ·cm or higher, andTOC (total organic material concentration) is preferably 20 ppb orlower, and it is preferred that water has been subjected to deaerationtreatment.

It is possible to heighten lithographic performance by increasing therefractive index of an immersion liquid. From such a point of view,additives capable of increasing the refractive index may be added towater, or heavy water (D₂O) may be used in place of water.

A film hardly soluble in an immersion liquid (hereinafter also referredto as “topcoat”) may be provided between a resist film by the positiveresist composition of the invention and an immersion liquid so as not tobring the resist film into direct contact with the immersion liquid. Thenecessary functions required of the topcoat are the aptitude for coatingon the upper layer of a resist, the transparency to radiation, inparticular the transparency to the ray of 193 nm, and the insolubilityin an immersion liquid. It is preferred that the topcoat is not mixedwith a resist and can be coated uniformly on a resist upper layer.

From the viewpoint of the transparency to 193 nm, a polymer notcontaining an aromatic group is preferred as the topcoat. Specifically,hydrocarbon polymers, acrylic ester polymers, polymethacrylic acid,polyacrylic acid, polyvinyl ether, silicon-containing polymers, andfluorine-containing polymers are exemplified. Considering thatimpurities eluting from a topcoat to the immersion liquid contaminatethe optical lens, the residual monomer components of the polymercontained in the topcoat is preferably less.

When the topcoat is peeled off, a developing solution may be used, or aremover may be used separately. As the remover, a solvent low inpenetration into a resist is preferred. In view of capable of performinga peeling process at the same time with the development process of aresist, it is preferred that the topcoat can be peeled off by an alkalideveloping solution. From the viewpoint of performing peeling with analkali developing solution, the topcoat is preferably acidic, but fromthe viewpoint of non-intermixture with the resist, it may be neutral oralkaline.

Resolution increases when there is no difference in the refractiveindexes between the topcoat and the immersion liquid. When water is usedas the immersion liquid in ArF excimer laser (wavelength: 193 nm)exposure, it is preferred that the refractive index of the topcoat forArF immersion exposure is nearer the refractive index of the immersionliquid. For bringing the refractive index of the topcoat nearer to thatof the immersion liquid, it is preferred for the topcoat to contain afluorine atom. Further, from the viewpoint of the transparency andrefractive index, the thickness of the topcoat is preferably thinner.

It is preferred that a topcoat should not be mixed with a resist, andfurther not mixed with an immersion liquid. From this point of view,when water is used as the immersion liquid, the solvent for a topcoat ispreferably hardly soluble in the solvent of the resist and a nonaqueousmedium. Further, when an immersion liquid is an organic solvent, thetopcoat may be aqueous or nonaqueous.

A resist composition in the invention as formed to a resist film has thereceding contact angle of water to the resist film of preferably 65° ormore. Here, the receding contact angle is the angle under normaltemperature and atmospheric pressure. The receding contact angle is thecontact angle of going back at the time when a resist film is inclinedand a droplet begins to drop.

In a development process, a developing solution is used as follows. Asthe alkali developing solution of a resist composition, alkaline aqueoussolutions of inorganic alkalis, e.g., sodium hydroxide, potassiumhydroxide, sodium carbonate, sodium silicate, sodium metasilicate,aqueous ammonia, etc., primary amines, e.g., ethylamine, n-propylamine,etc., secondary amines, e.g., diethylamine, di-n-butylamine, etc.,tertiary amines, e.g., triethylamine, methyldiethylamine, etc., alcoholamines, e.g., dimethylethanolamine, triethanolamine, etc., quaternaryammonium salts, e.g., tetramethylammonium hydroxide, tetraethylammoniumhydroxide, etc., and cyclic amines, e.g., pyrrole, piperidine, etc., canbe used.

An appropriate amount of alcohols and surfactants may be added to thesealkali developing solutions.

The alkali concentration of an alkali developing solution is generallyfrom 0.1 to 20 mass %.

The pH of an alkali developing solution is generally from 10.0 to 15.0.

EXAMPLE

The invention will be described with reference to examples, but theinvention is not restricted thereto.

Synthesis Examples of Compounds (A):

Synthesis Example 1 Synthesis of Compound (A-35)

A mixture comprising 10.86 g (78.6 mmol) of 4-hydroxy-benzoic acid, 16.1g (78.6 mmol) of (+)-chloromethyl menthyl ether, 12 ml of triethylamine,and 100 ml of acetone was stirred under nitrogen current at roomtemperature for 7 hours. To the mixture were added 200 ml of water and200 ml of ethyl acetate, the organic layer was washed with water, asaturated sodium chloride aqueous solution, and water in the order, andthe organic layer was dried with sodium sulfate. The solvent wasconcentrated, and the residue was purified by column chromatography(SiO₂, hexane/ethyl acetate: 10/1) to obtain 18.75 g of((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-methyl 4-hydroxybenzoateas a white solid. A mixture comprising 9.19 g (0.03 mol) of the solid,9.48 g (0.03 mol) of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyldifluoride, 5.0 g of triethylamine, and 130 ml of THF was stirred undernitrogen current at room temperature for 3 hours, and further stirredunder reflux for 2 hours. To the solution were added 200 ml of water and200 ml of ethyl acetate, the organic layer was washed with water, asaturated sodium chloride aqueous solution, and water in the order, andthe organic layer was dried with sodium sulfate. The solveni.wasconcentrated, and the residue was purified by column chromatography(SiO₂, hexane/ethyl acetate: 10/1) to obtain 15.26 g of an oily compoundhaving a structure shown below. A mixture comprising 3.9 g (6.47 mmol)of the oily compound, 50 ml of ethanol, 1.06 g of sodiumhydrogencarbonate, and 30 ml of water was stirred at room temperaturefor 10 hours. To the solution were added 200 ml of water and 200 ml ofethyl acetate, the organic layer was washed with water, a saturatedsodium chloride aqueous solution, and water in the order, and theorganic layer was dried with sodium sulfate. The solvent wasconcentrated, the residue was dissolved in 100 ml of methanol, and 2.22g (6.47 mmol) of triphenylsulfonium bromide was added thereto, followedby stirring at room temperature for 3 hours. Chloroform (200 ml) wasadded to the solution, the organic layer was washed with water, and theresidue was purified by column chromatography (SiO₂,chloroform/methanol: 10/1) to obtain 5.24 g of an oily compound (A-35).

¹H-NMR (400 MHz, CDCl₃)δ0.70 (d, 3H), 0.88(d, 3H), 0.92(d, 3H),1.23-1.45(m, 3H), 1.61-1.89 (m, 3H), 2.05-2.28 (m, 3H), 3.52(m, 1H),5.40-5.63 (AB-q, 2H), 7.38(d, 2H) 7.68-8.11(m, 15H), 8.12(d, 2H)

¹⁹F-NMR (400 MHz, CDCl₃) δ-118 (t, 2F), -114 (m, 2F), -107 (m, 2F)

Synthesis Example 2 Synthesis of Compound (A-36)

A mixture comprising 4.05 g (15.8 mmol) of4-(5-phenyl-1,3-dioxan-2-yl)phenol (synthesized according to the methoddescribed in J. Prakt. Chem., 323 (6), 902-913 (1981)), 5.0 g (15.8 mol)of 1,1,2,2,3,3-hexfluoropropane-1,3-disulfonyl difluoride, 1.76 g oftriethylamine, and 100 ml of THF was stirred under nitrogen current atroom temperature for 8 hours. To the solution were added 200 ml of waterand 200 ml of ethyl acetate, the organic layer was washed with water, asaturated sodium chloride aqueous solution, and water in the order, andthe organic layer was dried with sodium sulfate. The solvent wasconcentrated, and an oily compound having a structure shown below wasobtained. The oily compound (8.65 g) was dissolved in 100 ml of methanoland 50 ml of a 1M sodium hydroxide aqueous solution and stirred at roomtemperature for 2 hours. To the solution were added 200 ml of water and200 ml of ethyl acetate, the organic layer was washed with water, asaturated sodium chloride aqueous solution, and water in the order, andthe organic layer was dried with sodium sulfate. The solvent wasconcentrated, the residue was dissolved in 100 ml of methanol, and 5.28g of triphenylsulfonium bromide was added thereto, followed by stirringat room temperature for 3 hours. Chloroform (200 ml) was added to thesolution, the organic layer was washed with water to remove the solvent,whereby 9.60 g of a little brownish objective oily compound (A-36) wasobtained.

¹H-NMR (400 MHz, CDCl₃)δ3.35 (m, 1H), 4.05 (t, 2H), 4.35 (m, 2H), 5.60(s, 1H), 7.23-7.36 (m, 7H), 7.59 (d, 2H), 7.68-7.78 (m, 15H)

¹⁹F-NMR (400 MHz, CDCl₃)δ-118 (t, 2F), -114 (m, 2F), -107 (m, 2F)

Synthesis Example 3 Synthesis of Compound (A-39)

A mixture comprising 6.18 g (30 mmol) of4-hydroxy-3,5-diisopropylbenzaldehyde (synthesized according to themethod described in J. Med. Chem., 31 (1), 122-129 (1981)), 5.46 g (35.9mmol) of 2-phenylpropane-1,3-diol, 210 mg of p-toluenesulfonic acid, and50 ml of toluene was refluxed with heating under nitrogen current in aflask equipped with Dean-Stark water separator for 6 hours. The organiclayer was washed with a 1M sodium hydroxide aqueous solution, water, asaturated sodium chloride aqueous solution, and water in the order, andthe organic layer was dried with sodium sulfate. The solvent wasconcentrated, and the residue was purified by column chromatography(SiO₂, hexane/ethyl acetate: 10/1) to obtain 10.0 g of brown oil wasobtained. A mixture comprising 10.0 g (29.4 mmol) of the oil, 18.6 g(58.8 mol) of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl difluoride,60 ml of triethylamine, and 20 ml of THF was stirred under nitrogencurrent at 60° C. for 6 hours. To the solution were added 200 ml ofwater and 200 ml of ethyl acetate, the organic layer was washed withwater, a saturated sodium chloride aqueous solution, and water in theorder, and the organic layer was dried with sodium sulfate. The solventwas concentrated, and 16.5 g of oily compound having a structure shownbelow was obtained. The oily compound (16.5 g) was dissolved in 70 ml ofmethanol and 70 ml of a 1M sodium hydroxide aqueous solution, and thesolution was stirred at room temperature for 2 hours. To the solutionwere added 200 ml of water and 200 ml of ethyl acetate, the organiclayer was washed with water, a saturated sodium chloride aqueoussolution, and water in the order, and the organic layer was dried withsodium sulfate. The solvent was concentrated, the residue was dissolvedin 100 ml of methanol, and 9.08 g of triphenylsulfonium bromide wasadded thereto, and the solution was stirred at room temperature for 3hours. Chloroform (200 ml) was added to the solution, the organic layerwas washed with water, and the residue was purified by columnchromatography (SiO₂, chloroform/methanol: 10/1) to obtain 20.5 g of anobjective oily compound (A-39).

¹H-NMR (400 MHz, CDCl₃)δ1.22 (d, 12H), 3.44-3.50 (m, 3H), 4.04 (t, 2H),4.39 (m, 2H) 5.56 (s, 1H), 7.24-7.38 (m, 7H), 7.68-7.76 (m, 15H)

¹⁹F-NMR (400 MHz, CDCl₃)δ-118 (t, 2F), -114 (m, 2F), -108 (m, 2F)

Synthesis Example 4 Synthesis of Compound (A-45)

A mixture comprising 8.51 g (14.8 mmol) oftriphenyl-sulfonium1,1,2,2,3,3-hexafluoropropane-1-sulfonyl fluoride sulfonate, 2.52 g(19.2 mmol) of glycine t-butyl ester, 3.0 g of triethylamine, and 30 mlof THF was stirred under nitrogen current at 60° C. for 6 hours. To thesolution was added 200 ml of chloroform, the organic layer was washedwith water, and the residue was purified by column chromatography (SiO₂,chloroform/methanol: 10/1) to obtain 5.33 g of an objective pale yellowcompound (A-45) as a solid.

¹H-NMR (400 MHz, CDCl₃)δ-1.48 (s, 9H), 3.88 (m, 2H), -7.66-7.76 (m, 15H)

¹⁹F-NMR (400 MHz, CDCl₃)δ-119 (t, 2F), -114 (m, 2F), -112 (m, 2F)

Synthesis Example 5 Synthesis of Compound (A-48)

A mixture comprising 8.51 g (14.8 mmol) oftriphenyl-sulfonium1,1,2,2,3,3-hexafluoropropane-1-sulfonyl fluoride sulfonate, 5.10 g(19.2 mmol) of 2-(1-adamantyl)-2-propyl 2-aminoethylcarboxylate, 3.0 gof triethylamine, and 30 ml of THF was stirred under nitrogen current at60° C. for 6 hours. To the solution was added 200 ml of chloroform, theorganic layer was washed with water, and the residue was purified bycolumn chromatography (SiO₂, chloroform/methanol: 10/1) to obtain 6.2 gof an objective oily compound (A-48).

¹H-NMR (400 MHz, CDCl₃)δ1.44 (s, 6H), 1.61-1.69 (m, 12H), 2.00 (bs, 3H),2.52 (t, 2H) 3.09 (t, 2H), 7.66-7.78 (m, 15H)

¹⁹F-NMR (400 MHz, CDCl₃)δ-119 (t, 2F), -114 (m, 2F), -112 (m, 2F)

Synthesis Example 6 Synthesis of Compound (A-79)

4-Mercaptophenol (5.08 g) (40.3 mmol) and 10.0 g (40.3 mmol) of2-adamantylpropan-2-yl acrylate were dissolved in 100 ml of MeOH. To thesolution was added 4.08 g (40.3 mmol) of triethylamine and the solutionwas stirred at room temperature for 4 hours. Ethyl acetate (200 ml) wasadded to the solution, the organic layer was washed four times withsaturated sodium hydrogencarbonate and two times with water in order,and the organic layer was dried with sodium sulfate. The solvent wasconcentrated to obtain 11.2 g (29.9 mmol) of 2-adamantylpropan-2-yl3-(4-hydroxyphenylthio)propanoate as a white solid. A mixture comprising3.0 g (8.0 mmol) of the solid, 2.53 g (8.0 mmol) of1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl difluoride, 1.22 g (8 mmol)of 7,11-diazabicyclo[5.4.0]undec-11-ene, and 100 ml of acetonitrile wasstirred under nitrogen current at room temperature for 2 hours. Twohundred (200) ml of water and 200 ml of ethyl acetate were added to thesolution, and the organic layer was washed with water, a saturatedsodium chloride aqueous solution, and water in order, and the organiclayer was dried with sodium sulfate. The solvent was concentrated, andthe residue was dissolved in 50 ml of methanol and 50 ml of acetone.Sodium hydrogencarbonate (12.0 g) was added and the solution was stirredat 40° C. for 3 hours. Two hundred (200) ml of water and 200 ml of ethylacetate was added thereto and the organic layer was washed with water, asaturated sodium chloride aqueous solution, and water in order, and theorganic layer was dried with sodium sulfate. The solvent wasconcentrated to obtain brown oil. The oil was recrystallized withdiisopropyl ether, and 3.08 g (4.46 mmol) of sodium3-[4-{2-[(2-adamantylpropan-2-yloxy)carbonyl]ethylthio}-phenoxysulfonyl]-1,1,2,2,3,3-hexafluoropropane-1-sulfonatewas obtained as a white solid. The white solid (1.80 g) (2.61 mmol) wasdissolved in 100 ml of methanol, 0.895 g (2.61 mmol) oftriphenylsulfonyl bromide was added thereto, and the solution wasstirred at room temperature for 3 hours. Chloroform (200 ml) was addedto the solution, the organic layer was washed with water, and thesolvent was concentrated to obtain 2.63 g of a colorless transparentoily compound (A-79).

¹H-NMR (300 MHz, CDCl₃)δ1.457 (s, 6H), 1.590-1.681 (m, 12H), 1.997 (bs,3H), 2.570 (t, 2H), 3.151 (t, 2H), 7.201 (d, 2H), 7.335 (d, 2H),7.668-7.775 (m, 15H)

¹⁹F-NMR (300 MHz, CDCl₃)δ-107.25 (m, 2F), -114.03 (m, 2F), -118.40 (m,2F)

Other compounds (A) were also synthesized in the same manner.

Resin (C):

The structure, molecular weight and degree of molecular weightdispersion of each resin (C) used in Examples are shown below. Thenumber on the right side of the repeating unit is a molar ratio, and therest is the same.

In the following Tables 3 and 4, molar ratio of repeating units(corresponding to the order from the left side of the structuralformula), weight-average molecular weight (Mw) and degree of dispersionof molecular weight (Mw/Mn) with respect to (RA-27) to (RA-36) aredescribed. TABLE 3 Resin Composition (molar ratio) Mw Mw/Mn RA-2730/20/40/10 8000 2.0 RA-28 40/10/50 6000 1.8 RA-29 30/20/40/10 8500 1.5

TABLE 4 Resin Composition (molar ratio) Mw Mw/Mn RA-30 35/30/35 9800 1.8RA-31 30/40/30 9500 1.9 RA-32 25/25/50 6700 2.0 RA-33 50/25/25 12000 2.0RA-34 50/30/20 10000 2.0 RA-35 40/20/20/10 6400 2.1 RA-36 40/10/50 77002.0

Examples 1 to 37, Examples 74 to 81 and Comparative Examples 1 to 5

Preparation of resist:

A solution having the concentration of solids content of 12 mass % wasprepared by dissolving the components shown in Tables 5 and 6 below inthe solvent shown in Tables 5 and 6, and a positive resist solution wasprepared by filtrating the above-prepared solution through apolytetrafluoroethylene filter or a polyethylene filter having a poresize of 0.1 μm. The thus prepared positive resist solution was evaluatedas follows. The results obtained are shown in Tables 5 and 6.

Evaluation of Resist:

Exposure Condition (1)

An antireflection film DUV-42 (manufactured by Brewer Science) wasuniformly coated on a silicone substrate subjected tohexamethyldisilazane treatment in a thickness of 600 Å by a spin coater,and dried on a hot plate at 100° C. for 90 seconds, and then dried byheating at 190° C. for 240 seconds. After that, each positive resistsolution was coated thereon by a spin coater and dried at 120° C. for 90seconds to form a resist film having a thickness of 0.25 μm.

The resist film was subjected to exposure through a mask with an ArFexcimer laser stepper (NA: 0.6, manufactured by ISI Co.), and heated ona hot plate at 120° C. for 90 seconds just after exposure. Further, theresist film was developed with a 2.38 mass % tetramethylammoniumhydroxide aqueous solution at 23° C. for 60 seconds, rinsed with purewater for 30 seconds, and then dried, whereby a line pattern was formed.

Exposure condition (2)

In condition (2), a resist pattern was formed by immersion exposure withpure water.

An organic antireflection film ARC29A (manufactured by Nissan ChemicalIndustries, Ltd.) was coated on a silicone wafer, and the coated layerwas baked at 205° C. for 60 seconds to form an antireflection filmhaving a thickness of 78 nm. The positive resist solution prepared wascoated on the antireflection film and baked at 120° C. for 60 seconds,whereby a resist film having a thickness of 250 nm was formed. Theobtained wafer was subjected to pattern exposure with an ArF excimerlaser immersion scanner (NA: 0.75). Super pure water of impurities of 5ppb or less was used as the immersion liquid. After that, the resistfilm was heated at 120° C. for 60 seconds, developed with a 2.38 mass %tetramethylammonium hydroxide aqueous solution for 30 seconds, rinsedwith pure water, and then dried by spinning to obtain a resist pattern.

Resist patterns formed by exposure conditions (1) and (2) were evaluatedas follows.

Exposure Latitude:

Taking the exposure amount required to reproduce the mask pattern ofline and space of line width 90 nm as the optimal exposure amount, thebreadth of exposure amount tolerating 90 nm ±10% of a pattern size whenexposure amount was varied was found. The obtained value was divided bythe optimal exposure amount and shown in percentage as the exposurelatitude. The greater the value, the smaller is the fluctuation inperformance by the variation of exposure amount, so that exposurelatitude is good. Line edge roughness:

In regard to the edge of the range of 5 μm in the machine direction ofthe line pattern, the distance from the intrinsic base line of the edgewas measured at 50 points with an SEM (S-8840, manufactured by Hitachi,Ltd.), and the standard deviation was found, from which 3σ was computed.The smaller the value, the better is the performance. TABLE 5 ExposureExposure Condition Condition Acid (I) (II) Generator Dissolution Ex-Line Ex- Line Compound Used in Basic Solvent Inhibiting posure Edgeposure Edge (A) Combination Resin Compound Surfactant (mass CompoundLatitude Roughness Latitude Roughness Ex. No. (g) (g) (10 g) (g) (0.03g) ratio) (g) (%) (nm) (%) (nm) Ex. 1 A-1 (0.1) z38 (0.3) RA-20 PEA/TPAW-4 A1/B1 (60/40) 13.5 4.3 16.3 3.7 (0.02/0.02) Ex. 2 A-2 (0.2) z60, 38RA-1 PEA/DIA W-4 A1/B1 (80/20) LCB (0.2) 15.4 4.2 15.4 4.6 (0.3/0.4)(0.01/0.02) Ex. 3 A-4 (0.2) z68 (0.4) RA-4 PEA (0.02) W-4 A1/B1 (60/40)16.3 4.2 15.6 5.2 Ex. 4 A-5 (0.3) z78 (0.3) RA-20 DIA (0.02) W-4 A1/B2(80/20) 18.7 4.8 14.2 5.4 Ex. 5 A-6 (0.2) z60 (0.4) RA-24 PEA/DIA W-4A1/B2 (80/20) 12.4 5.1 16.6 4.3 (0.02/0.02) Ex. 6 A-7 (0.3) z34 (0.4)RA-25 PEA/DIA W-4 A1/B1 (60/40) 15.4 4.8 14.7 5.1 (0.01/0.02) Ex. 7 A-8(0.3) z66 (0.3) RA-24 PEA/DIA W-4 A1/B1 (80/20) 15.9 3.9 18.2 4.6(0.02/0.02) Ex. 8 A-10 (0.4) z65 (0.4) RA-4 PEA (0.02) W-4 A1/A3 (60/40)15.9 4.1 14.9 5.1 Ex. 9 A-11 (0.5) z63 (0.15) RA-23 PEA (0.02) W-2 A1/B1(70/30) 16.8 4.6 16.8 4.2 Ex. 10 A-15 (0.3) z63 (0.3) RA-20 PEA (0.02)W-4 A1/A4 (60/40) 16.3 5.1 17.4 4.8 Ex. 11 A-22 (0.2) z38, 63 RA-22 PEA(0.02) W-4 A1/B1 (60/40) LCB (0.1) 15.4 4.9 14.0 5.1 (0.4/0.4) Ex. 12A-24 (0.3) z63 (0.3) RA-20 PEA (0.02) W-2 A1/B1 (70/30) 17.1 4.2 13.04.8 Ex. 13 A-25 (0.3) z75 (0.3) RA-1 PEA (0.02) W-4 A1/B1 (80/20) 17.53.8 19.7 3.8 Ex. 14 A-26 (0.3) z63 (0.4) RA-5 PEA/DIA W-4 A1/B1 (60/40)18.0 4.8 20.2 4.8 (0.01/0.01) Ex. 15 A-33 (0.3) z78 (0.1) RA-20 PEA(0.02) W-2 A1/B2 (80/20) 15.9 4.2 22.9 4.9 Ex. 16 A-35 (0.3) z60 (0.3)RA-20 PEA/DIA W-4 A1/B1 (60/40) 13.5 5.1 21.1 4.9 (0.02/0.02) Ex. 17A-36 (0.3) z64 (0.3) RA-26 PEA (0.02) W-1 A1/B1 (80/20) LCB (0.3) 16.44.2 22.9 3.2 Ex. 18 A-39 (0.3) z70 (0.2) RA-25 DIA (0.02) W-4 A1/A3(60/40) 14.9 4.9 13.5 5.1 Ex. 19 A-40 (0.3) z72 (0.4) RA-3 PEA (0.02)W-4 A1/A4 (60/40) 16.3 4.5 15.4 4.8 Ex. 20 A-45 (0.4) z60, 68 RA-6PEA/DIA W-4 A1/B1 (80/20) 15.9 4.0 16.3 5.3 (0.4/0.2) (0.01/0.01) Ex. 21A-46 (0.3) z64 (0.3) RA-6 PEA (0.02) W-4 A1/B2 (80/20) 13.5 5.1 18.7 4.2Ex. 22 A-48 (0.3) z38, 63 RA-22 DIA (0.02) W-2 A1/B1 (60/40) 15.4 5.812.4 4.9 (0.4/0.4) Ex. 23 A-50 (0.4) z60 (0.3) RA-26 PEA (0.02) W-4A1/B1 (80/20) 16.3 3.8 15.4 5.6 Ex. 24 A-56 (0.3) z38 (0.3) RA-23 TMEA(0.03) W-4 A1/A3 (60/40) 18.7 4.9 20.2 4.6 Ex. 25 A-61 (0.3) z69 (0.5)RA-26 PEA/DIA W-4 A1/B1 (80/20) LCB (0.2) 12.4 5.5 22.9 3.2 (0.02/0.01)Ex. 26 A-64 (0.3) z60 (0.3) RA-8 PEA (0.03) W-4 A1/A3 (60/40) 15.4 5.620.6 4.2 Ex. 27 A-65 (0.2) z61 (0.3) RA-21 PEA (0.02) W-1 A1/A4 (60/40)15.9 5.7 22.9 4.8 Ex. 28 A-69 (0.4) z50 (0.4) RA-15 PEA (0.03) W-4 A1/B1(80/20) 15.9 4.9 13.5 3.1 Ex. 29 A-71 (0.4) z60 (0.4) RA-24 TMEA (0.03)W-2 A1/A3 (80/20) 16.8 5.0 15.4 4.8 Ex. 30 A-72 (0.35) z38 (0.5) RA-20DIA (0.02) W-4 A1/B1 (80/20) 18.4 4.3 16.3 3.8 Ex. 31 A-35 (0.3) — (—)RA-1 — (—) — A1/B1 (60/40) 18.8 4.2 15.4 4.8 Ex. 32 A-73 (0.25) z38(0.3) RA-1 PEA (0.03) W-4 A1/B1 (80/20) 15.6 3.9 16.1 4.6 Ex. 33 A-74(0.4) z78 (0.3) RA-4 PEA (0.02) W-4 A1/B2 (80/20) 16.1 3.4 16.8 4.8 Ex.34 A-75 (0.3) z60 (0.3) RA-8 PEA (0.03) W-4 A1/A4 (60/40) 18.2 4.5 17.03.1 Ex. 35 A-76 (0.3) z38 (0.3) RA-15 DIA (0.03) W-4 A1/B1 (80/20) 17.94.1 16.2 3.5 Ex. 36 A-77 (0.3) z78 (0.3) RA-21 PEA/DIA W-4 A1/A3 (60/40)16.2 4.2 15.3 3.6 (0.02/0.01) Ex. 37 A-35 (0.3) z60 (0.3) RA-1 PEA/DIAW-4 A1/B1 (60/40) 18.8 4.2 15.4 4.8 A-78 (0.1) RA-20 (0.01/0.01) Comp. —(—) z38 (0.3) RA-1 PEA (0.03) W-4 A1/B1 (60/40) 8.9 8.5 9.8 9.6 Ex. 1Comp. TPSB (0.3) z38 (0.4) RA-4 PEA/DIA W-4 A1/B1 (80/20) LCB (0.2) 9.111.3 8.9 8.6 Ex. 2 (0.02/0.01) Comp. TPSPB z38 (0.4) RA-19 DIA (0.03)W-1 A1/B1 (80/20) 8.2 9.2 8.5 10.1 Ex. 3 (0.3) Comp. — (—) z60 (0.4)RA-5 PEA (0.03) W-4 A1/A3 (60/40) 7.4 11.3 8.0 9.8 Ex. 4 Comp. — (—) z38(0.3) RA-20 TMEA (0.03) W-1 A1/A3 (60/40) 10.0 9.1 11.1 9.2 Ex. 5

TABLE 6 Exposure Exposure Condition Condition (I) (II) Acid GeneratorDissolution Ex- Line Ex- Line Compound Used in Basic Solvent Inhibitingposure Edge posure Edge (A) Combination Resin Compound Surfactant (massCompound Latitude Roughness Latitude Roughness Ex. No. (g) (g) (10 g)(g) (0.03 g) ratio) (g) (%) (nm) (%) (nm) Ex. 74 A-79 (0.3) z78 (0.3)RA-28 PEA (0.02) W-4 A1/A3 (60/40) 19.5 5.1 18.0 4.9 Ex. 75 A-81 (0.3)z78 (0.3) RA-27 PBI (0.015) W-4 A1/A3 (80/20) 16.8 5.2 17.1 5.8 Ex. 76A-83 (0.2) z63 (0.4) RA-32 PEA (0.02) W-4 A1/A3 (60/40) 15.2 4.6 19.25.0 Ex. 77 A-87 (0.3) z78 (0.3) RA-35 DIA (0.02) W-4 A1/A3 (80/20) 16.85.0 16.9 4.5 Ex. 78 A-92 (0.3) z78 (0.3) RA-36 PEA (0.02) W-4 A1/A3(60/40) 17.1 4.3 17.8 4.7 Ex. 79 A-93 (0.2) z60 (0.3) RA-27 PBI (0.015)W-4 A1/A3 (60/40) 18.0 4.8 16.9 4.9 Ex. 80 A-79 (0.3) z78 (0.3) RA-28DIA (0.02) W-4 A1/B1 (80/20) 19.0 4.9 19.0 5.2 Ex. 81 A-89 (0.3) z78(0.4) RA-28 PEN/DIA W-4 A1/A3 (80/20) 14.2 5.0 17.8 5.5 (0.02/0.01)

The abbreviations common to each table are enumerated together below.

Comparative compounds:

The abbreviations of comparative compounds used in Comparative Examplesare as follows.TPSB: Triphenylsulfonium Pentafluorobenzenesulfonate

TPSPB: Triphenylsulfonium Perfluorobutanesulfonate

Basic Compounds:

-   TPI: 2,4,5-Triphenylimidazole-   TPSA: Triphenylsulfonium Acetate-   HEP: N-Hydroxyethyl Piperidine-   DIA: 2,6-Diisopropylaniline-   DCMA: Dicyclohexylmethylamine-   TPA: Tripentylamine-   HAP: Hydroxyantipyrine-   TBAH: Tetrabutylammonium Hydroxide-   TMEA: Tris(methoxyethoxyethyl)amine-   PEA: N-Phenyldiethanolamine-   TOA: Trioctylamine-   DBN: 1,5-Diazabicyclo[4.3.0]Non-5-Ane-   PBI: 2-Phenylbenzoimidazole    Surfactants:-   W-1: Megafac F176 (fluorine surfactant, manufactured by Dainippon    Ink and Chemicals Inc.)-   W-2: Megafac R08 (fluorine/silicon surfactant, manufactured by    Dainippon Ink and Chemicals Inc.)-   W-3: Polysiloxane polymer KP-341 (silicon surfactant, manufactured    by Shin-Etsu Chemical Co., Ltd.)-   W-4: Troy Sol S-366 (manufactured by Troy Chemical Co., Ltd.)    Solvents:-   A1: Propylene glycol monomethyl ether acetate-   A2: 2-Heptanone-   A3: Cyclohexanone-   A4: γ-Butyrolactone-   B1: Propylene glycol monomethyl ether-   B2: Ethyl lactate    Dissolution Inhibiting Compounds:-   LCB: t-Butyl lithocholate

From the results shown in Tables 5 and 6, it is apparently seen that thephotosensitive compositions in the invention are excellent in exposurelatitude and line edge roughness in ArF ordinary exposure and ArFimmersion exposure.

Examples 38 to 43 and Comparative Examples 6 to 10

(1) Formation of Lower Resist Layer

FHi-028DD resist (resist for i-ray, manufactured by Fuji Film Olin Co.,Ltd.) was coated on a 6 inch silicone wafer with a spin coater Mark 8(manufactured by Tokyo Electron Limited), baked at 90° C. for 90seconds, whereby a uniform film having a thickness of 0.55 μm wasobtained.

The obtained film was further heated at 200° C. for 3 minutes to obtaina lower resist layer having a thickness of 0.40 μm.

(2) Formation of Upper Resist Layer

A solution having the concentration of solids content of 11 mass % wasprepared by dissolving the components shown in Table 7 below in thesolvent shown in Table 7. The solution was filtrated through a membranefilter having a pore diameter of 0.1 μm, whereby a composition for anupper resist layer was prepared.

The upper resist layer coating solution was coated on the lower resistlayer in the same manner as in the lower layer, and heated at 130° C.for 90 seconds, whereby an upper resist layer having a thickness of 0.20μm was formed.

Resins (SI-1) to (SI-5) in Table 3 are as follows. Molecular Weight(SI-1)

15000 (SI-2)

14500 (SI-3)

9600 (SI-4)

8900 (SI-5)

10800(3) Evaluation of Resist

The thus-obtained wafer was subjected to exposure with ArF ExcimerStepper 9300 (manufactured by ISI Co.) attached with a resolution maskwith varying the exposure amount.

Subsequently, after heating at 120° C. for 90 seconds, the wafer wasdeveloped with a 2.38 mass % tetrahydroammonium hydroxide developingsolution for 60 seconds, rinsed with distilled water and dried to obtainan upper layer pattern. The exposure latitude and line edge roughness ofthe resist were evaluated in the same manner as in Example 1.

The results obtained are shown in Table 7 below. TABLE 7Silicon-containing Positive Acid Generator Used in Basic Exposure LineEdge Example Compound (A) Combination Resin Compound Surfactant SolventLatitude Roughness No. (g) (g) (10 g) (g) (0.03 g) (mass ratio) (%) (nm)Ex. 38 A-35 (0.3) z38 (0.4) SI-1 PEA (0.02) W-4 A1/A3 (80/20) 14.4 4.5Ex. 39 A-36 (0.3) z60 (0.3) SI-2 DIA (0.02) W-4 A1/A3 (60/40) 16.3 3.9Ex. 40 A-39 (0.4) z38 (0.3) SI-2 PEA (0.02) W-3 A1/A3 (80/20) 13.9 4.2Ex. 41 A-45 (0.3) z38 (0.4) SI-3 TPA (0.03) W-4 A1 (100) 15.6 4.6 Ex. 42A-48 (0.3) z60 (0.3) SI-4 DIA (0.02) W-4 A1 (100) 16.2 4.2 Ex. 43 A-50(0.5) z38 (0.3) SI-4 DIA (0.03) W-1 A1 (100) 15.4 4.2 Comp. — (—) z38(0.3) SI-1 PEA (0.02) W-1 A1 (100) 8.6 5.7 Ex. 6 Comp. TPSB (0.3) z38(0.4) SI-2 PEA (0.03) W-4 A1/A3 (60/40) 9.5 6.7 Ex. 7 Comp. TPSPB (0.3)z38 (0.3) SI-5 PEA (0.03) W-4 A1/B1 (70/30) 9.9 8.9 Ex. 8 Comp. — (—)z60 (0.4) SI-3 DIA (0.03) W-4 A1 (100) 10.1 10.2 Ex. 9 Comp. — (—) z38(0.4) SI-4 TPA (0.04) W-4 A1/A3 (60/40) 9.8 8.2 Ex. 10

From the results shown in Table 3, it is apparently seen that thephotosensitive compositions in the invention are also excellent inexposure latitude and line edge roughness when used as two-layeredresists.

Examples 44 to 49 and Comparative Examples 11 to 15

Preparation of Resist:

A positive resist solution having the concentration of solids content of14 mass % was prepared by dissolving the components shown in Table 8below in the solvent, and filtrating the solution through apolytetrafluoroethylene filter having a pore size of 0.1 μm.

Evaluation of resist:

The prepared positive resist solution was uniformly coated on a siliconesubstrate subjected to hexamethyl-disilazane treatment by a spin coater,and dried by heating on a hot plate at 120° C. for 90 seconds to form aresist film having a thickness of 0.4 μm.

The resist film was subjected to exposure through a mask for line andspace with a KrF excimer laser stepper (NA: 0.63), and heated on a hotplate at 110° C. for 90 seconds just after exposure. Further, the resistfilm was developed with a 2.38 mass % tetramethylammonium hydroxideaqueous solution at 23° C. for 60 seconds, rinsed with pure water for 30seconds, and then dried, whereby a line pattern was formed. The exposurelatitude and line edge roughness of the resist were evaluated in thesame manner as in Example 1.

The results obtained are shown in Table 8 below. TABLE 8 KrF PositiveAcid Generator Dissolution Line Compound Used in Basic SolventInhibiting Exposure Edge (A) Combination Resin Compound Surfactant (massCompound Latitude Roughness Ex. No. (g) (g) (10 g) (g) (0.03 g) ratio)(g) (%) (nm) Ex. 44 A-35 (0.3) z38 (0.4) R-2 PEA (0.04) W-4 A1/B1(60/40) 15.9 3.8 Ex. 45 A-36 (0.3) z60 (0.3) R-7 PEA/DIA (0.01/0.02) W-4A1/B1 (60/40) 13.5 4.9 Ex. 46 A-39 (0.4) z38 (0.3) R-8 TMEA (0.02) W-4A1/A3 (60/40) LCB (0.1) 14.0 4.2 Ex. 47 A-45 (0.3) z60 (0.4) R-9 PEA(0.04) W-4 A1/B1 (70/30) 13.3 4.3 Ex. 48 A-48 (0.3) z38 (0.3) R-14 PEA(0.02) W-1 A1/A4 (80/20) 12.2 4.1 Ex. 49 A-50 (0.5) z38 (0.3) R-17 PEA(0.02) W-2 A1/A4 (80/20) 14.9 4.8 Comp. — (—) z38 (0.3) R-2 PEA (0.02)W-4 A1/B1 (60/40) 9.1 9.8 Ex. 11 Comp. TPSB (0.3) z38 (0.4) R-7 DIA(0.03) W-4 A1/B1 (80/20) 10.9 8.9 Ex. 12 Comp. TPSPB (0.3) z38 (0.3) R-8PEA (0.03) W-4 A1/A3 (60/40) 8.2 10.2 Ex. 13 Comp. — (—) z60 (0.4) R-9DIA (0.03) W-4 A1/B1 (70/30) 10.2 9.2 Ex. 14 Comp. — (—) z38 (0.4) R-14DIA (0.02) W-1 A1/A3 (60/40) 9.5 9.9 Ex. 15

The molar ratio of repeating units and weight average molecular weightof each of resins (R-2), (R-7), (R-8), (R-9), (R-14) and (R-17) used inTable 8 are shown in Table 9 below. TABLE 9 Molar Ratio of WeightRepeating Units Average (correspondent from Molecular Resin the left inorder) Weight R-2 60/20/20 12,000 R-7 60/30/10 18,000 R-8 60/20/2012,000 R-9 60/40 13,000 R-14 60/15/25 12,000 R-17 80/20 15,000

From the results shown in Table 8, it is apparently seen that thephotosensitive compositions in the invention are also excellent inexposure latitude and line edge roughness as the positive resistcompositions in KrF excimer laser exposure.

Examples 50 to 55 and Comparative Examples 16 to 20

Preparation of resist:

A negative resist solution having the concentration of solids content of14 mass % was prepared by dissolving the components shown in Table 10below in the solvent, and filtrating the solution through apolytetrafluoroethylene filter having a pore size of 0.1 μm.

Each of the prepared negative resist solutions was evaluated in the samemanner as in Example 44, and the results obtained are shown in Table 10.TABLE 10 KrF Negative Acid Generator Line Compound Used in SolventCrosslinking Exposure Edge Example (A) Combination Resin Basic CompoundSurfactant (mass Agent Latitude Roughness No. (g) (g) (10 g) (g) (0.03g) ratio) (g) (%) (nm) Ex. 50 A-35 (0.3) z38 (0.4) P-1 PEA (0.02) W-4A1/B1 (60/40) CL-1 (3) 14.9 4.2 Ex. 51 A-36 z60 (0.4) P-1 HAP (0.02) W-4A1/B1 (60/40) CL-4 (4) 16.8 3.7 Ex. 52 A-39 z38 (0.3) P-2 PEA (0.03) W-1A1/A3 (60/40) CL-1 (2) 16.4 4.8 Ex. 53 A-45 (0.3) z60 (0.4) P-2 PEA(0.02) W-2 A1/B1 (70/30) CL-1 (2) 14.9 4.4 Ex. 54 A-48 (0.3) z38 (0.3)P-1 PEA/DIA W-4 A1/A4 (80/20) CL-1 (2) 13.5 5.2 (0.01/0.02) Ex. 55 A-50(0.3) z38 (0.3) P-2 PEA (0.03) W-3 A1/A3 (80/20) CL-1 (3) 16.3 4.5 Comp.— (—) z38 (0.3) P-1 HAP (0.02) W-4 A1/B1 (60/40) CL-1 (2) 7.8 9.5 Ex. 16Comp. TPSB (0.3) z38 (0.4) P-2 DIA (0.03) W-4 A1/B1 (60/40) CL-4 (4) 9.97.6 Ex. 17 Comp. TPSPB (0.3) z38 (0.3) P-2 PEA (0.03) W-4 A1/B1 (60/40)CL-4 (4) 8.5 10.5 Ex. 18 Comp. — (—) z60 (0.4) P-3 DIA (0.04) W-4 A1/B1(80/20) CL-1 (2) 7.6 11.3 Ex. 19 Comp. — (—) z38 (0.4) P-3 PEA (0.02)W-2 A1/B1 (70/30) CL-5 (2) 10.6 9.0 Ex. 20

The structures, molecular weights, and molecular weight distributions ofthe alkali-soluble resins and crosslinking agents in Table 10 are shownbelow. Mw Mw/Mn P-1

16000 2.30 P-2

12000 1.2 P-3

6000 1.2

VP-5000 (manufactured by Nippon Soda Co., Ltd.)

From the results shown in Table 10, it is apparently seen that thephotosensitive compositions in the invention are also excellent inexposure latitude and line edge roughness as the negative resistcompositions in KrF excimer laser exposure.

Examples 56 to 61 and Comparative Examples 21 to 25

Preparation of resist:

Preparation of resist:

A positive resist solution having the concentration of solids content of12 mass % was prepared by dissolving the components shown in Table 8 inthe solvent, and filtrating the solution through apolytetrafluoroethylene filter having a pore size of 0.1 μm.

Evaluation of Resist:

The prepared positive resist solution was uniformly coated on a siliconesubstrate subjected to hexamethyl-disilazane treatment by a spin coater,and dried by heating on a hot plate at 120° C. for 60 seconds to form aresist film having a thickness of 0.3 μm.

The resist film was irradiated by an electron beam projectionlithographic apparatus (accelerating voltage: 100 keV, manufactured byNikon Corporation), and heated on a hot plate at 110° C. for 90 secondsjust after irradiation. Further, the resist film was developed with a2.38 mass % tetramethyl-ammonium hydroxide aqueous solution at 23° C.for 60 seconds, rinsed with pure water for 30 seconds, and then dried,whereby a line and space pattern was formed. The exposure latitude andline edge roughness of the resist were evaluated in the same manner asin Example 1.

The results obtained are shown in Table 11 below. TABLE 11 EB PositiveExposure Line Edge Latitude Roughness Example No. (%) (nm) Example 5614.0 4.8 Example 57 16.5 4.9 Example 58 14.5 4.9 Example 59 18.2 5.2Example 60 14.8 5.1 Example 61 16.7 4.8 Comparative 9.1 9.2 Example 21Comparative 8.6 9.9 Example 22 Comparative 10.0 9.6 Example 23Comparative 10.6 8.3 Example 24 Comparative 9.6 11.1 Example 25

From the results shown in Table 11, it is apparently seen that thephotosensitive compositions in the invention are also excellent inexposure latitude and line edge roughness as the positive resistcompositions for electron beam irradiation.

Examples 62 to 67 and Comparative Examples 26 to 30

Preparation of Resist:

A negative resist solution having the concentration of solids content of12 mass % was prepared by dissolving the components shown in Table 10 inthe solvent, and filtrating the solution through apolytetrafluoroethylene filter having a pore size of 0.1 μm.

Evaluation of Resist:

The prepared negative resist solution was uniformly coated on a siliconesubstrate subjected to hexamethyl-disilazane treatment by a spin coater,and dried by heating on a hot plate at 120° C. for 60 seconds to form aresist film having a thickness of 0.3 μm.

The resist film was irradiated by an electron beam projectionlithographic apparatus (accelerating voltage: 100 keV, manufactured byNikon Corporation), and heated on a hot plate at 110° C. for 90 secondsjust after irradiation. Further, the resist film was developed with a2.38 mass % tetramethyl- ammonium hydroxide aqueous solution at 23° C.for 60 seconds, rinsed with pure water for 30 seconds, and then dried,whereby a line and space pattern was formed. The exposure latitude andline edge roughness of the resist were evaluated in the same manner asin Example 1.

The results obtained are shown in Table 12 below. TABLE 12 EB NegativeExposure Line Edge Latitude Roughness Example No. (%) (nm) Example 6213.3 4.8 Example 63 16.3 5.1 Example 64 14.8 5.8 Example 65 16.2 5.1Example 66 15.7 4.9 Example 67 13.3 4.2 Comparative 9.1 7.9 Example 26Comparative 8.1 8.5 Example 27 Comparative 8.6 9.6 Example 28Comparative 8.0 10.2 Example 29 Comparative 9.6 11.0 Example 30

From the results shown in Table 12, it is apparently seen that thephotosensitive compositions in the invention are also excellent inexposure latitude and line edge roughness as the negative resistcompositions for electron beam irradiation.

Examples 68 to 73 and Comparative Examples 31 to 35

A positive resist solution having the concentration of solids content of8 mass % was prepared by dissolving the components shown in Table 8 inthe solvent, and filtrating the solution through apolytetrafluoroethylene filter having a pore size of 0.1 μm.

Evaluation of Resist:

The prepared positive resist solution was uniformly coated on a siliconesubstrate subjected to hexamethyl-disilazane treatment by a spin coater,and dried by heating on a hot plate at 120° C. for 60 seconds to form aresist film having a thickness of 0.15 μm. The obtained resist film wassubjected to a real exposure with EUV ray (wavelength: 13 nm) withvarying exposure amount 0.5 by 0.5 mJ within the range of exposureamount of from 0 to 10.0 mJ, and the resist film was further baked at110° C. for 90 seconds. After that, a dissolving rate of the resist filmat each exposure amount was measured with a 2.38% tetramethylammoniumhydroxide (TMAH) aqueous solution, and a sensitivity curve was obtained.In the sensitivity curve, the exposure amount at the time when thedissolving rate of the resist was saturated was taken as sensitivity,and dissolving contrast (γ value) was computed from the gradient of thestraight line part of the sensitivity curve. The greater the γ value,the better is the dissolving contrast.

The results of evaluations obtained are shown in Table 13 below. TABLE13 Extreme Ultraviolet Radiation Sensitivity Example No. (mJ/cm2) ΓValue Example 68 2.6 17.9 Example 69 2.9 19.5 Example 70 2.5 18.5Example 71 2.3 16.9 Example 72 2.2 19.2 Example 73 2.7 17.8 Comparative5.6 8.6 Example 31 Comparative 7.8 9.2 Example 32 Comparative 6.2 9.2Example 33 Comparative 8.0 9.9 Example 34 Comparative 6.1 9.6 Example 35

From the results shown in Table 13, it can be seen that the resistcompositions in the invention are high sensitivity, high contrast andexcellent in the characteristic evaluation by irradiation with EUV raysas compared with comparative compositions.

The invention can provide a photosensitive composition that shows goodline edge roughness and exposure latitude, and improved in the contrastof sensitivity and dissolution in UV exposure, a pattern-forming methodusing the photosensitive composition, and compounds in thephotosensitive composition. The invention can further provide aphotosensitive composition suitable for immersion exposure having goodperformances as described above even in immersion exposure, apattern-forming method using the photosensitive composition, andcompounds in the photosensitive composition.

The entire disclosure of each and every foreign patent application fromwhich the benefit of foreign priority has been claimed in the presentapplication is incorporated herein by reference, as if fully set forth.

1. A photosensitive composition, which comprises (A) a compound capable of generating an organic acid represented by formula (I) upon irradiation with actinic ray or radiation: Z—A—X—B—R  (I) wherein Z represents an organic acid group; A represents a divalent linking group; X represents a single bond or a divalent linking group having a hetero atom; B represents a single bond, an oxygen atom or —N(Rx)—; Rx represents a hydrogen atom or a monovalent organic group; and R represents a monovalent organic group having a bond that is cut by an action of an acid, and when B represents —N(Rx)—, R and Rx may be bonded to form a ring.
 2. The photosensitive composition according to claim 1, wherein Z represents a sulfo group or a carboxyl group.
 3. The photosensitive composition according to claim 1, wherein A represents an alkylene group.
 4. The photosensitive composition according to claim 3, wherein A represents an alkylene group in which a part or whole of hydrogen atoms is substituted with fluorine atoms.
 5. The photosensitive composition according to claim 1, wherein X is selected from the group consisting of a single bond, —SO₂—, —SO— and —CO—.
 6. The photosensitive composition according to claim 1, wherein the compound capable of generating an organic acid represented by formula (I) upon irradiation with actinic ray or radiation is a sulfonium salt compound of an organic acid represented by formula (I) or an iodonium salt compound of an organic acid represented by formula (I).
 7. A pattern-forming method, which comprises: forming a photosensitive film with a photosensitive composition according to claim 1; and exposing and developing the photosensitive film.
 8. An organic acid represented by formula (I) and a salt of the organic acid: Z—A—X—B—R  (I) wherein Z represents an organic acid group; A represents a divalent linking group; X represents a single bond or a divalent linking group having a hetero atom; B represents a single bond, an oxygen atom or —N(Rx)—; Rx represents a hydrogen atom or a monovalent organic group; and R represents a monovalent organic group having a bond that is cut by an action of an acid, and when B represents —N(Rx)—, R and Rx may be bonded to form a ring.
 9. A compound capable of generating an organic acid represented by formula (I) upon irradiation with actinic ray or radiation: Z—A—X—B—R  (I) wherein Z represents an organic acid group; A represents a divalent linking group; X represents a single bond or a divalent linking group having a hetero atom; B represents a single bond, an oxygen atom or —N(Rx)—; Rx represents a hydrogen atom or a monovalent organic group; and R represents a monovalent organic group having a bond that is cut by an action of an acid, and when B represents —N(Rx)—, R and Rx may be bonded to form a ring.
 10. The photosensitive composition according to claim 1, wherein the bond that is cut by an action of an acid in the monovalent organic group represented by R is formed by an ester bond, an acetal bond or a carbonate bond.
 11. The photosensitive composition according to claim 1, wherein the compound capable of generating an organic acid represented by formula (I) upon irradiation with actinic ray or radiation is a compound represented by formula (A1) (A2):

wherein R₂₀₁, R₂₀₂ and R₂₀₃ each independently represents an organic group; R₂₀₄ and R₂₀₅ each independently represents an aryl group, an alkyl group or a cycloalkyl group; and X⁻ represents an anion of the organic acid represented by formula (I). 